Method for transmitting/receiving signals by using beams in wireless communication system, and device for same

ABSTRACT

The present specification provides a method for transmitting/receiving signals through beams in a wireless communication system. The signal transmission/reception method performed by a terminal, in the present specification, may comprise the steps of: receiving a beam reference signal used in beam management from an eNB via a first Rx beam; if beam reporting is triggered, reporting to the eNB a measurement result based on the beam reference signal; receiving, from the eNB, control information related to the determination of a second Rx beam for receiving a particular signal; and receiving the particular signal via the second Rx beam on the basis of the received control information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2018/000038, filed on Jan. 2, 2018,which claims the benefit of U.S. Provisional Application No. 62/441,569filed on Jan. 3, 2017, U.S. Provisional Application No. 62/472,496 filedon Mar. 16, 2017, U.S. Provisional Application No. 62/475,900 filed onMar. 24, 2017, U.S. Provisional Application No. 62/479,384 filed on Mar.31, 2017 and U.S. Provisional Application No. 62/521,258 filed on Jun.16, 2017 the contents of which are all hereby incorporated by referenceherein in their entirety.

TECHNICAL FIELD

The present invention relates to a wireless communication system and,more particularly, to a signal transmission and reception method using abeam and an apparatus supporting the same.

BACKGROUND ART

A mobile communication system has been developed to provide a voiceservice while ensuring an activity of a user. However, in the mobilecommunication system, not only a voice but also a data service isextended. At present, due to an explosive increase in traffic, there isa shortage of resources and users demand a higher speed service, and asa result, a more developed mobile communication system is required.

Requirements of a next-generation mobile communication system should beable to support acceptance of explosive data traffic, a dramaticincrease in per-user data rate, acceptance of a significant increase inthe number of connected devices, very low end-to-end latency, andhigh-energy efficiency. To this end, various technologies areresearched, which include dual connectivity, massive multiple inputmultiple output (MIMO), in-band full duplex, non-orthogonal multipleaccess (NOMA), super wideband support, device networking, and the like.

DISCLOSURE Technical Problem

This specification is to provide a method of transmitting and receivinginformation on the reception of a beam for receiving a specific signalor a PDCCH.

Furthermore, this specification is to define an operation method of auser equipment depending on whether beam reception information forreceiving a PDCCH has been received.

Furthermore, this specification is to define the Rx beam of a userequipment configured for each PDCCH when a plurality of PDCCHs istransmitted and an operation of the user equipment according to the Rxbeam.

Furthermore, this specification is to provide a method of transmittingand receiving information related to an Rx beam for receiving a PDSCH.

Technical objects to be achieved in the present invention are notlimited to the aforementioned object, and those skilled in the art towhich the present invention pertains may evidently understand othertechnological objects from the following description.

Technical Solution

This specification provides a method of transmitting and receivingsignals through at least one reception beam in a wireless communicationsystem signal. The method performed by a user equipment includesreceiving, from a base station, a beam reference signal used for beammanagement through a first reception beam; reporting, to the basestation, a measurement result based on the beam reference signal whenbeam reporting is triggered; receiving, from the base station, controlinformation related to a determination of a second reception beam forreceiving a specific signal; and receiving the specific signal throughthe second reception beam based on the received control information,wherein when a plurality of specific signals is received throughdifferent symbols included in a specific time domain, the controlinformation is configured for each specific resource.

Furthermore, in this specification, the specific signal is a physicaldownlink control channel (PDCCH).

Furthermore, in this specification, the control information indicates aresource quasi co-located (QCL) with a resource of a demodulationreference signal (DMRS) for the PDCCH reception.

Furthermore, in this specification, the resource quasi co-located (QCL)with the resource of the demodulation reference signal (DMRS) for thePDCCH reception is a resource of the beam reference signal.

Furthermore, in this specification, receiving, from the base station,the control information includes receiving, from the base station,information for a given number of beam sets for receiving the PDCCHthrough first signaling; and receiving, from the base station,information indicating a specific beam set configured for each specifictime unit through second signaling.

Furthermore, in this specification, priority is set for each of thegiven number of beam sets.

Furthermore, in this specification, the specific time domain includes atleast one time gap determined by taking into consideration at least oneof the decoding time of the control information or beam switchinglatency between reception beams for the reception of a plurality of thePDCCHs.

Furthermore, this specification further includes transmitting, to thebase station, UE capability information indicating a capability of theUE related to the beam switching latency.

Furthermore, this specification further includes receiving, from thebase station, information related to the at least one time gap. Theinformation related to the at least one time gap includes at least oneof the number of time gaps included in the specific time domain orduration of the time gap.

Furthermore, this specification further includes receiving, from thebase station, a confirm message for providing notification of updatedinformation related to a beam if the information related to the beam isupdated based on the beam reporting.

Furthermore, in this specification, the control information isrepresented as a bitmap.

Furthermore, this specification further includes receiving, from thebase station, indication information indicating a third reception beamfor receiving a physical downlink shared channel (PDSCH); and receiving,from the base station, a physical downlink shared channel (PDSCH) basedon the received indication information.

Furthermore, in this specification, the indication information indicatesa preconfigured reception beam or indicates a reception beam identicalwith a second reception beam.

Furthermore, in this specification, the PDSCH is received after aspecific offset from timing in which the indication information isreceived. The specific offset is determined by taking into considerationat least one of a decoding time for the indication information or beamswitching latency.

Furthermore, this specification provides a user equipment transmittingand receiving signals through at least one Rx beam in a wirelesscommunication system, including a radio frequency (RF) module configuredto transmit and receive radio signals and a processor functionallyconnected to the RF module. The processor is configured to receive, froma base station, a beam reference signal used for beam management througha first reception beam; report, to the base station, a measurementresult based on the beam reference signal when beam reporting istriggered; receive, from the base station, control information relatedto a determination of a second reception beam for receiving a specificsignal; and receive the specific signal through the second receptionbeam based on the received control information, wherein when a pluralityof specific signals is received through different symbols included in aspecific time domain, the control information is configured for eachspecific resource.

The specific resource is a physical downlink control channel (PDCCH).

Advantageous Effects

This specification has an effect in that it can reduce the decodingnumber of a user equipment by defining contents related to an Rx beamfor receiving a specific signal or a PDCCH.

Furthermore, this specification has an effect in that it can prevent aproblem in that a payload size increases and latency that may occur forsignal transmission and reception by hierarchically transmittingspecific information.

Effects which may be obtained in the present invention are not limitedto the aforementioned effects, and various other effects may beevidently understood by those skilled in the art to which the presentinvention pertains from the following description.

DESCRIPTION OF DRAWINGS

The accompany drawings, which are included as part of the detaileddescription in order to help understanding of the present invention,provide embodiments of the present invention and describe the technicalcharacteristics of the present invention along with the detaileddescription.

FIG. 1 is a diagram showing an example of a general system structure ofNR to which a method proposed in this specification may be applied.

FIG. 2 shows the relation between an uplink frame and a downlink framein a wireless communication system to which a method proposed in thisspecification may be applied.

FIG. 3 shows an example of a resource grid supported in a wirelesscommunication system to which a method proposed in this specificationmay be applied.

FIG. 4 shows examples of a resource grid for each antenna port andnumerology to which a method proposed in this specification may beapplied.

FIG. 5 shows examples of a connection method of a TXRU and an antennaelement.

FIG. 6 shows various shows examples of a service area for each TXRU.

FIG. 7 shows an example of a Tx-Rx beam configuration between an eNB anda user equipment to which a method proposed in this specification may beapplied.

FIG. 8 shows an example in which QCL for a new spatial parameter hasbeen configured for each control symbol, which is proposed in thisspecification.

FIG. 9 is a diagram showing an example in which a time gap has beenallocated within a multi-symbol PDCCH, which is proposed in thisspecification.

FIG. 10 shows an example of a control channel and in which differentbeams are used for corresponding data channel transmission to which amethod proposed in this specification may be applied.

FIG. 11 is a flowchart showing an example of a method of transmittingand receiving a plurality of signals using different Rx beams, which isproposed in this specification.

FIG. 12 is a flowchart showing an example of a method of indicating aPDSCH Rx beam using a physical control channel, which is proposed inthis specification.

FIG. 13 illustrates a block diagram of a wireless communication deviceaccording to an embodiment of the present invention.

FIG. 14 illustrates a block diagram of a communication device accordingto an embodiment of the present invention.

MODE FOR INVENTION

Some embodiments of the present disclosure are described in detail withreference to the accompanying drawings. A detailed description to bedisclosed along with the accompanying drawings is intended to describesome exemplary embodiments of the present disclosure and is not intendedto describe a sole embodiment of the present disclosure. The followingdetailed description includes more details in order to provide fullunderstanding of the present disclosure. However, those skilled in theart will understand that the present disclosure may be implementedwithout such more details.

In some cases, in order to avoid making the concept of the presentdisclosure vague, known structures and devices are omitted or may beshown in a block diagram form based on the core functions of eachstructure and device.

In the present disclosure, a base station has the meaning of a terminalnode of a network over which the base station directly communicates witha terminal. In this document, a specific operation that is described tobe performed by a base station may be performed by an upper node of thebase station according to circumstances. That is, it is evident that ina network including a plurality of network nodes including a basestation, various operations performed for communication with a terminalmay be performed by the base station or other network nodes other thanthe base station. The base station (BS) may be substituted with anotherterm, such as a fixed station, a Node B, an evolved-NodeB (eNB), a basetransceiver system (BTS), or an access point (AP). Furthermore, theterminal may be fixed or may have mobility and may be substituted withanother term, such as a user equipment (UE), a mobile station (MS), auser terminal (UT), a mobile subscriber station (MSS), a subscriberstation (SS), an advanced mobile station (AMS), a wireless terminal(WT), a machine-type communication (MTC) device, a machine-to-Machine(M2M) device, or a device-to-device (D2D) device.

Hereinafter, downlink (DL) means communication from a base station to aUE, and uplink (UL) means communication from a UE to a base station. Inthe DL, a transmitter may be part of a base station, and a receiver maybe part of a UE. In the UL, a transmitter may be part of a UE, and areceiver may be part of a base station.

Specific terms used in the following description have been provided tohelp understanding of the present disclosure, and the use of suchspecific terms may be changed in various forms without departing fromthe technical sprit of the present disclosure.

The following technologies may be used in a variety of wirelesscommunication systems, such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and non-orthogonalmultiple access (NOMA). CDMA may be implemented using a radiotechnology, such as universal terrestrial radio access (UTRA) orCDMA2000. TDMA may be implemented using a radio technology, such asglobal system for mobile communications (GSM)/general packet radioservice (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA maybe implemented using a radio technology, such as Institute of electricaland electronics engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX),IEEE 802.20, or evolved UTRA (E-UTRA). UTRA is part of a universalmobile telecommunications system (UMTS). 3rd generation partnershipproject (3GPP) Long term evolution (LTE) is part of an evolved UMTS(E-UMTS) using evolved UMTS terrestrial radio access (E-UTRA), and itadopts OFDMA in downlink and adopts SC-FDMA in uplink. LTE-advanced(LTE-A) is the evolution of 3GPP LTE.

Embodiments of the present disclosure may be supported by the standarddocuments disclosed in at least one of IEEE 802, 3GPP, and 3GPP2, thatis, radio access systems. That is, steps or portions that belong to theembodiments of the present disclosure and that are not described inorder to clearly expose the technical spirit of the present disclosuremay be supported by the documents. Furthermore, all terms disclosed inthis document may be described by the standard documents.

In order to more clarify a description, 3GPP LTE/LTE-A is chieflydescribed, but the technical characteristics of the present disclosureare not limited thereto.

Definition of Terms

eLTE eNB: eLTE eNB is the evolution of an eNB which supports aconnection to EPC and NGC.

gNB: A node which supports not only a connection to NGC but also NR.

New RAN: A wireless access network which supports NR or E-UTRA orinteracts with NGC.

Network slice: A network slice is a network defined by an operator toprovide a solution optimized to a specific market scenario requiringspecific requirements together with an end-to-end scope.

Network function: A network function is a logical node within networkinfrastructure having a well-defined external interface and awell-defined functional operation.

NG-C: A control plane interface used for an NG2 reference point betweena new RAN and NGC.

NG-U: A user plane interface used for an NG3 reference point between anew RAN and NGC

Non-standalone NR: A disposition configuration by which a gNB requiresan LTE eNB as an anchor to establish a control plane connection to anEPC or by which a gNB requires an eLTE eNB as an anchor to establish acontrol plane connection to an NGC.

Non-standalone E-UTRA: A disposition configuration which requires a gNBas an anchor to establish a control plane connection to an NGC.

User plane gateway: An end-point of the NG-U interface.

System in General

FIG. 1 illustrates one example of the overall system structure of an NRto which a method proposed by the present specification may be applied.

Referring to FIG. 1, an NG-RAN is composed of an NG-RA user plane (a newAS sublayer/PDCP/RLC/MAC/PHY) and gNBs providing control plane (RRC)protocol endpoints for User Equipment (UE).

The gNBs are inter-connected through an Xn interface.

The gNBs are also connected to the NGC through the NG interface.

More specifically, the gNBs are connected to Access and MobilityManagement Functions (AMFs) through the N2 interface and to User PlaneFunctions (UPFs) through the N3 interface.

New Rat (NR) Numerology and Frame Structure

In the NR system, a plurality of numerologies may be supported. In thiscase, the numerology may be defined by a subcarrier spacing and cyclicprefix (CP) overhead. In this case, a plurality of the subcarrierspacing may be derived by scaling a basic subcarrier spacing in integerN (or μ). Furthermore, although it is assumed that a very low subcarrierspacing is not used in a very high carrier frequency, a numerology usedmay be selected independently of a frequency band.

Furthermore, in the NR system, various frame structures according to aplurality of numerologies may be supported.

Hereinafter, orthogonal frequency division multiplexing (OFDM)numerologies and frame structures which may be taken into considerationin the NR system are described.

A plurality of OFDM numerologies supported in the NR system may bedefined as in Table 1.

TABLE 1 μ Δf = 2^(μ) · 15 [kHz] Cyclic prefix 0 15 Normal 1 30 Normal 260 Normal, Extended 3 120 Normal 4 240 Normal 5 480 Normal

In relation to a frame structure of the NR system, the size of variousfields in a time domain is represented as a multiple of a time unit ofT_(s)=1/(Δf_(max)·N_(f)). In this case, Δf_(max)=480·10³ and N_(f)=4096.Downlink and uplink transmission are configured with a radio framehaving a period of T_(f)=(Δf_(max)N_(f)/100)·T_(s)=10 ms. In this case,the radio frame is configured with 10 subframes having a period of eachT_(sf)=(Δf_(max)N_(f)/1000)·T_(s)=1 ms. In this case, there may be oneset of frames for the uplink and one set of frames for the downlink.

FIG. 2 shows the relation between an uplink frame and a downlink framein a wireless communication system to which a method proposed in thisspecification may be applied.

As shown in FIG. 2, the transmission of an uplink frame number i from auser equipment (UE) needs to be started prior to T_(TA)=N_(TA)T_(s)compared to the start of a corresponding downlink frame in thecorresponding UE.

With respect to a numerology μ, slots are numbered in order of highern_(s) ^(μ)∈{0, . . . , N_(subframe) ^(slots,μ)−1} within a subframe, andthe slots are numbered in order of higher n_(s,f) ^(μ)∈{0, . . . ,N_(frame) ^(slots,μ)−1} within a radio frame. One slot is configuredwith contiguous N_(symb) ^(μ) OFDM symbols, and N_(symb) ^(μ) isdetermined based on a used numerology and slot configuration. The startof a slot n_(s) ^(μ) within the subframe is temporally aligned with thestart of an OFDM symbol n_(s) ^(μ)N_(symb) ^(μ) in the same subframe.

All UEs cannot perform transmission and reception at the same time, andthis means that all the OFDM symbols of a downlink slot or an uplinkslot cannot be used.

Table 2 shows the number of OFDM symbols per slot for a normal CP in anumerology μ, and Table 3 shows the number of OFDM symbols per slot foran extended CP in the numerology μ.

TABLE 22 Slot configuration 0 1 μ N_(symb) ^(μ) N_(frame) ^(slots, μ)N_(subframe) ^(slots, μ) N_(symb) ^(μ) N_(frame) ^(slots, μ)N_(subframe) ^(slots, μ) 0 14 10 1 7 20 2 1 14 20 2 7 40 4 2 14 40 4 780 8 3 14 80 8 — — — 4 14 160 16 — — — 5 14 320 32 — — —

TABLE 3 Slot configuration 0 1 μ N_(symb) ^(μ) N_(frame) ^(slots, μ)N_(subframe) ^(slots, μ) N_(symb) ^(μ) N_(frame) ^(slots, μ)N_(subframe) ^(slots, μ) 0 12 10 1 6 20 2 1 12 20 2 6 40 4 2 12 40 4 680 8 3 12 80 8 — — — 4 12 160 16 — — — 5 12 320 32 — — —

NR Physical Resource

In relation to a physical resource of an NR system, an antenna port, aresource grid, a resource element, a resource block, a carrier part,etc. may be taken into consideration.

Hereinafter, physical resources which may be taken into consideration inthe NR system are described specifically.

First, in relation to the antenna port, the antenna port is defined sothat a channel on which a symbol on the antenna port is carried isdeduced from a channel on which a different symbol on the same antennaport is carried. If the large-scale property of a channel on which asymbol on one antenna port is carried can be deduced from a channel onwhich a symbol on a different antenna port is carried, the two antennaports may be said to have a quasi co-located or quasi co-location(QC/QCL) relation. In this case, the large-scale property includes oneor more delay spread, Doppler spread, a frequency shift, averagereceived power, or received timing.

FIG. 3 shows an example of a resource grid supported in a wirelesscommunication system to which a method proposed in this specificationmay be applied.

FIG. 3 illustrates that a resource grid is configured with N_(RB)^(μ)N_(sc) ^(RB) subcarriers on a frequency domain and one subframe isconfigured with 14·2μ OFDM symbols, but is not limited thereto.

In an NR system, a transmitted signal is described by one or moreresource grids configured with N_(RB) ^(μ)N_(sc) ^(RB) subcarriers andOFDM symbols of 2^(μ)N_(symb) ^((μ)). In this case, N_(RB) ^(μ)≤N_(RB)^(max,μ). The N_(RB) ^(max,μ) indicates a maximum transmissionbandwidth, which may be different between the uplink and the downlink inaddition to between numerologies.

In this case, as in FIG. 4, one resource grid may be configured for eachnumerology μ and each antenna port p.

FIG. 4 shows examples of a resource grid for each antenna port andnumerology to which a method proposed in this specification may beapplied.

Each element of the resource grid for a numerology μ and an antenna portp is denoted as a resource element and uniquely identified by an indexpair (k,l). In this case, k=0, . . . , N_(RB) ^(μ)N_(sc) ^(RB)−1 is anindex on a frequency domain, and l=0, . . . , 2^(μ)N_(symb) ^((μ))−1denotes the position of a symbol within a subframe. When a resourceelement is denoted in a slot, an index pair (k,l) is used. In this case,l=0, . . . , N_(symb) ^(μ)−1.

The resource element (k,l) for the numerology μ and the antenna port pcorresponds to a complex value a_(k,l) ^(p,μ)). If there is no danger ofconfusion or if a specific antenna port or numerology is not specified,indices p and μ may be dropped. As a result, a complex value may be ora_(k,l) ^((p)) or a_(k,l) .

Furthermore, a physical resource block is defined as contiguous N_(sc)^(RB)=12 subcarriers on a frequency domain. On the frequency domain,physical resource blocks are numbered from 0 to N_(RB) ^(μ)−1. In thiscase, the relation between a physical resource block number n_(PRB) andresource elements (k,l) on the frequency domain is given as in Equation1.

$\begin{matrix}{n_{PRB} = \lfloor \frac{k}{N_{sc}^{RB}} \rfloor} & \lbrack {{Equation}\mspace{14mu} 1} \rbrack\end{matrix}$

Furthermore, in relation to a carrier part, a UE may be configuredreceive or transmit only a subset of a resource grid. In this case, aset of resource blocks configured to be received or transmitted by theUE is numbered from 0 to N_(URB) ^(μ)−1 on the frequency domain.

Uplink Control Channel

Physical uplink control signaling needs to carry at least hybrid-ARQacknowledgement, CSI report (including beamforming information, ifpossible), and a scheduling request.

At least two transmission methods for an uplink control channelsupported in an NR system are supported.

An uplink control channel may be transmitted in short duration in theperiphery of an uplink symbol(s) transmitted at the last of a slot. Inthis case, the uplink control channel is time-division-multiplexedand/or frequency-division-multiplexed with an UL data channel within theslot. 1-symbol unit transmission of a slot is supported for an uplinkcontrol channel in short duration.

-   -   Short uplink control information (UCI) and data are        frequency-division-multiplexed in a UE and between UEs if        physical resource blocks (PRBs) for short UCI and data do not        overlap at least.    -   In order to support the time division multiplexing (TDM) of        short PUCCHs from different UEs within the same slot, a        mechanism for notifying a UE of whether a symbol(s) within a        slot in which a short PUCCH will be transmitted is supported at        least 6 GHz or more is supported.    -   At least 1) when a reference signal (RS) is multiplexed, UCI and        the RS are multiplexed in a given OFDM symbol according to a        frequency division multiplexing (FDM) method and 2) a subcarrier        spacing between DL/UL data and a PUCCH of short duration in the        same slot is the same are supported for 1-symbol duration.    -   At least, a PUCCH of short duration across 2-symbol duration of        a slot is supported. In this case, a subcarrier spacing between        DL/UL data and a PUCCH of short duration in the same slot is the        same.    -   At least, a semi-static configuration in which the PUCCH        resources of a given UE within a slot, that is, the short PUCCHs        of different UEs, can be time-division multiplexed within given        duration in the slot is supported.    -   A PUCCH resource includes a time domain, a frequency domain, and        a code domain, if applicable.    -   A PUCCH of short duration may be extended up to the end of a        slot in the UE viewpoint. In this case, after the PUCCH of short        duration, an explicit gap symbol is not necessary.    -   With respect to a slot having a short uplink part (i.e.,        DL-centric slot), if data is scheduled in the short uplink part,        “short UCI” and the data may be frequency-division multiplexed        by one UE.

An uplink control channel may be transmitted in long duration over aplurality of uplink symbols in order to improve coverage. In this case,the uplink control channel is frequency-division multiplexed with anuplink data channel within a slot.

-   -   UCI carried by a long duration UL control channel may be        transmitted in one slot or a plurality of slots, at least, with        the design having a low peak to average power ratio (PAPR).    -   Transmission using a plurality of slots is permitted for total        duration (e.g., 1 ms) at least partially.    -   In the case of a long duration UL control channel, time division        multiplexing (TDM) between an RS and UCI is supported for a        DFT-S-OFDM.    -   The long UL part of a slot may be sued for PUCCH transmission of        long duration. That is, a PUCCH of long duration is supported        for an UL-only slot and all slots having a variable number of        symbols configured with a minimum of 4 symbols.    -   with respect to at least 1- or 2-bit UCI, the UCI may be        repeated within N slots (N>1). The N slots may neighbor or may        not neighbor in slots in which a PUCCH of long duration is        permitted.    -   At least the simultaneous transmission of a PUSCH and a PUCCH is        supported for a long PUCCH. That is, although data is present,        uplink control for a PUCCH resource is transmitted. Furthermore,        in addition to the PUCCH-PUSCH simultaneous transmission, UCI in        a PUSCH is supported.    -   Intra-TTI slot frequency hopping is supported.    -   A DFT-s-OFDM waveform is supported.    -   Transmission antenna diversity is supported.

TDM and FDM between a PUCCH of short duration and a PUCCH of longduration are supported for different UEs in one slot, at least. In afrequency domain, a PRB (or a plurality of PRBs) is a minimum resourceunit size for an uplink control channel. If hopping is used, a frequencyresource and hopping may not be spread to a carrier bandwidth.Furthermore, a UE-specific RS is used for NR-PUCCH transmission. A setof PUCCH resources is configured by higher layer signaling. The PUCCHresources within the configured set are indicated by downlink controlinformation (DCI).

As part of DCI, timing between data reception and hybrid-ARQacknowledgement transmission needs to be indicated dynamically (alongwith at least RRC). A combination of a semi-static configuration anddynamic signaling (for at least some types of UCI information) is usedto determine a PUCCH resource for a “long and short PUCCH format.” Inthis case, the PUCCH resource includes a time domain, a frequencydomain, and a code domain, if applicable. To use UCI on the PUSCH, thatis, to use some of resources for UCI, is supported for the simultaneoustransmission of the UCI and data.

Furthermore, at least the uplink transmission of a single HARQ-ACK bitis supported at least. Furthermore, a mechanism that enables frequencydiversity is supported. Furthermore, in the case of ultra-reliable andlow-latency communication (URLLC), a time interval between schedulingrequest (SR) resources configured for a UE may be smaller than one slot.

Beam Management

In NR, beam management is defined as follows.

Beam management: a TRP(s) which may be used for DL and UL transmissionand reception and/or a set of L1/L2 procedures for obtaining andmaintaining a set of UE beams include at least the following contents:

-   -   Beam decision: an operation for a TRP(s) or a UE to select its        own transmission/Rx beam.    -   Beam measurement: an operation for a TRP(s) or a UE to measure        the characteristics of a received beamforming signal.    -   Beam reporting: an operation for a UE to report information on a        beamformed signal based on beam measurement.    -   Beam sweeping: an operation of covering a space region using a        Tx and/or Rx beam during a time interval according to a        pre-determined method.

Furthermore, a Tx/Rx beam correspondence in a TRP and a UE is defined asfollows.

-   -   A Tx/Rx beam correspondence in a TRP is maintained when at least        one of the followings is satisfied.    -   A TRP may determine a TRP Rx beam for uplink reception based on        the downlink measurement of a UE for one or more Tx beams of a        TRP.    -   A TRP may determine a TRP Tx beam for downlink transmission        based on the uplink measurement of a TRP for one or more Rx        beams of the TRP.    -   A Tx/Rx beam correspondence in a UE is maintained when at least        one of the followings is satisfied.    -   A UE may determine a UE Tx beam for uplink transmission based on        the downlink measurement of a UE for one or more Rx beams of the        UE.    -   A UE may determine a UE Rx beam for downlink reception based on        the indication of a TRP based on uplink measurement for one or        more Tx beams.    -   The capability indication of UE beam correspondence-related        information is supported for a TRP.

The following DL L1/L2 beam management procedure is supported within oneTRP or a plurality of TRPs.

P-1: this is used to enable UE measurement for different TRP Tx beams inorder to support the selection of a TRP Tx beam/UE Rx beam(s).

-   -   In general, beamforming in a TRP includes intra/inter-TRP Tx        beam sweep in different beam sets. For beamforming in a UE, it        commonly includes UE Rx beam sweep from a set of different        beams.

P-2: UE measurement for different TRP Tx beams is used to change aninter/intra-TRP Tx beam(s).

P-3: if a UE uses beamforming, UE measurement for the same TRP Tx beamis used to change a UE Rx beam.

Aperiodic reporting (aperiodic reporting) triggered by at least anetwork is supported in P-1-, P-2- and P-3-related operations.

UE measurement based on an RS for beam management (at least a CSI-RS) isconfigured with K (a total number of beams) beams. A UE reports ameasurement result of selected N Tx beams. In this case, N is not anessentially fixed number. A procedure based on an RS for a mobilityobject is not excluded. Reporting information includes at least ameasurement quantity for an N beam(s) and information indicating an N DLTx beam when N<K. Particularly, a UE may report a CSI-RS resourceindicator (CRI) of N′ with respect to K′>1 non-zero power (NZP) CSI-RSresources.

A UE may be configured with the following higher layer parameters forbeam management.

-   -   N≥1 reporting setting, M≥1 resource setting    -   Links between reporting settings and resource settings are        configured in an agreed CSI measurement configuration.    -   P-1 and P-2 based on a CSI-RS are supported as resource and        reporting settings.    -   P-3 may be supported regardless of whether a reporting setting        is present.    -   Reporting setting including at least the following contents    -   Information indicating a selected beam    -   L1 measurement reporting    -   A time domain operation (e.g., aperiodic operation, a periodic        operation, a semi-persistent operation)    -   Frequency granularity when several frequency granularities are        supported    -   Resource setting including at least the following contents    -   A time domain operation (e.g., an aperiodic operation, a        periodic operation, semi-persistent operation)    -   RS type: at least an NZP CSI-RS    -   At least one CSI-RS resource set. Each CSI-RS resource set may        include K≥1 CSI-RS resources (some parameters of K CSI-RS        resources may be the same. For example, a port number, a time        domain operation, density and a period)

Furthermore, NR supports the following beam reporting by taking intoconsideration an L group where L>1.

-   -   Information indicating a minimum group    -   A measurement quantity for an N1 beam (support L1 RSRP and CSI        report (if a CSI-RS is for CSI acquisition))    -   If applicable, information indicating N₁ DL Tx beams

Group-based beam reporting, such as that described above, may beconfigured in a UE unit. Furthermore, the group-based beam reporting maybe turned off in a UE unit (e.g., when L=1 or N₁=1).

NR supports that a UE can trigger a mechanism for recovery from a beamfailure.

A beam failure event occurs when the quality of a beam pair link of anassociated control channel is sufficient low (e.g., a comparison with athreshold and the timeout of an associated timer). The mechanism forrecovery from a beam failure (or obstacle) is triggered when a beamobstacle occurs.

A network explicitly configures a resource for transmitting an UL signalwith respect to a UE for a recovery object. The configuration ofresources is supported at the place where an eNB listens to theresources from all or some of directions (e.g., random access region).

An UL transmission/resource reporting a beam obstacle may be positionedat the same time instance as that of a PRACH (resource orthogonal to aPRACH resource) or at time instance (configurable for a UE) differentfrom that of a PRACH. The transmission of a DL signal is supported sothat a UE can monitor a beam in order to identify new potential beams.

NR supports beam management regardless of beam-related indication. Ifbeam-related indication is provided, information on a UE-sidebeamforming/reception procedure used for CSI-RS-based measurement may beindicated for a UE through QCL. Parameters for delay, Doppler, and anaverage gain used in the LTE system and a spatial parameter forbeamforming in a receiver will be added as a QCL parameter to besupported in NR. The QCL parameter may include a parameter related to anangle of arrival in a UE Rx beamforming viewpoint and/or parametersrelated to an angle of departure in an eNB Rx beamforming viewpoint. NRsupports that the same or different beams are used for control channeland corresponding data channel transmission.

For NR-PDCCH transmission supporting the robustness of beam pair linkblocking, a UE may be configured to monitor NR-PDCCHs on an M-beam pairlink at the same time. In this case, a maximum value of M≥1 and M maydepend on at least UE capability.

A UE may be configured to monitor an NR-PDCCH on a different beam pairlink(s) in different NR-PDCCH OFDM symbols. A parameter related to UE Rxbeam setting for monitoring an NR-PDCCH on a plurality of beam pairlinks is configured by higher layer signaling or a MAC CE and/or istaken into consideration in the search space design.

At least, NR supports the indication of a spatial QCL assumption betweena DL RS antenna port(s) and a DL RS antenna port(s) for the demodulationof a DL control channel. A candidate signaling method for beamindication for an NR-PDCCH (i.e., a configuration method of monitoringan NR-PDCCH) includes MAC CE signaling, RRC signaling, DCI signaling, aspec. transparent and/or implicit method, and a combination of thesignaling methods.

For the reception of a unicast DL data channel, NR supports theindication of a spatial QCL assumption between a DL RS antenna port andthe DMRS antenna port of a DL data channel.

Information indicating an RS antenna port is indicated through DCI(downlink permission). Furthermore, the information indicates an RSantenna port QCLed with a DMRS antenna port. A different set of DMRSantenna ports for a DL data channel may be indicated as QCL with adifferent set of RS antenna ports.

Hereinafter, prior to the detailed description of methods proposed inthis specification, contents related to the methods proposed in thisspecification directly/indirectly are first described in brief.

In next-generation communication, such as 5G or New Rat (NR), as morecommunication devices require a higher communication capacity, there isa need for enhanced mobile broadband communication compared to theexisting radio access technology (RAT).

Furthermore, massive machine type communications (MTC) that providesvarious services anywhere and at any time by connecting a plurality ofdevices and things is also one of important issues that may be takeninto consideration in the next-generation communication.

Furthermore, the design or structure of a communication system in whichservice and/or a UE sensitive to reliability and latency are taken intoconsideration is discussed.

As described above, the introduction of the next-generation radio accesstechnology (RAT) in which enhanced mobile broadband (eMBB)communication, massive MTC (mMTC), and ultra-reliable and low latencycommunication (URLLC) are taken into consideration is being discussed.In this specification, the corresponding technology is generally called“new RAT (NR)”, for convenience sake.

OFDM Numerology in NR

A new RAT system uses an OFDM transmission method or a transmissionmethod similar to the method, and has an OFDM numerology of Table 4representatively.

That is, Table 4 shows an example of OFDM parameters of a New RATsystem.

TABLE 4 Parameter Value Subcarrier-spacing (Δf) 60 kHz OFDM symbollength 16.33 us Cyclic Prefix (CP) length 1.30 us/1.17 us System BW 80MHz No. of available subcarriers 1200 Subframe length 0.25 ms Number ofOFDM symbol per Subframe 14 symbols

Analog Beamforming

In a millimeter wave (mmW), multiple antenna elements may be installedin the same area because a wavelength is short.

That is, in a 30 GHz band, a wavelength is 1 cm, and a total of 64 (8×8)antenna elements may be installed in a panel of 4×4 cm at intervals of0.5 lambda (wavelength) in a 2-dimensional array form.

Therefore, in mmW, coverage is increased or throughput is improved byraising a beamforming (BF) gain using multiple antenna elements.

In this case, if each antenna element has a transceiver unit (TXRU) sothat transmission power and a phase can be adjusted, independentbeamforming is possible for each frequency resource.

However, there is a problem in that effectiveness is low in terms of theprice if TXRUs are installed in all of 100 antenna elements.

Therefore, a method of mapping multiple antenna elements to one TXRU andadjusting the direction of a beam using an analog phase shifter is takeninto consideration.

Such an analog beamforming method has a disadvantage in that it cannotperform frequency-optional beamforming because only one beam directioncan be formed in a full band.

For this reason, hybrid BF (HBF) having the number of BTXRUs smallerthan Q antenna elements in the middle form of digital BF and analog BFmay be taken into consideration.

HBF is different depending on a method of connecting B TXRUs and Qantenna elements, but the direction of beams that may be transmitted atthe same time is limited to B or less.

FIG. 5 shows examples of a connection method of a TXRU and an antennaelement.

In this case, a TXRU virtualization model shows the relation between theoutput signal of a TXRU and the output signals of antenna elements.

FIG. 5a shows an example of a method of connecting a TXRU to asub-array.

Referring to FIG. 5a , an antenna element is connected to only one TXRU.Unlike FIG. 5a , FIG. 5b shows a method of connecting TXRUs to allantenna elements.

That is, in the case of FIG. 5b , the antenna elements are connected toall TXRUs.

In FIG. 5, W indicates a phase vector multiplied by an analog phaseshifter.

That is, the direction of analog beamforming is determined by W. In thiscase, mapping between CSI-RS antenna ports and TXRUs may be 1-to-1 or1-to-many.

Reference Signal (RS) Virtualization

In mmW, PDSCH transmission is possible in one analog beam direction atone timing by analog beamforming.

Therefore, an eNB transmits data to only some UEs in a specificdirection.

Accordingly, data transmission may be performed to a plurality of UEs inseveral analog beam directions at the same time by differentlyconfiguring analog beam directions for each antenna port, if necessary.

FIG. 6 shows various shows examples of a service region for each TXRU.

FIG. 6 shows an example of a structure in which 256 antenna elements areequally divided into four parts to form four sub-arrays and a TXRU isconnected to each sub-array.

If each sub-array is configured with a total of 64 (8×8) antennaelements in a 2-dimensional array form, a region corresponding to ahorizontal angle region of 15 degrees and a vertical angle region of 15degrees may be covered by specific analog beamforming.

That is, a region that needs to be served by an eNB is divided intomultiple regions, and the regions are served one by one at once.

In the following description, it is assumed that a CSI-RS antenna portand a TXRU are 1-to-1 mapped.

Accordingly, an antenna port and a TXRU may be construed as having thesame meaning.

As in FIG. 6a , if all TXRUs (antenna ports, sub-array) have the sameanalog beamforming direction, the throughput of a corresponding regionmay be increased by forming a digital beam having higher resolution.

Furthermore, the throughput of a corresponding region may be increasedby increasing the rank of transmission data to the corresponding region.

Furthermore, as in FIG. 6b , if each TXRU (antenna port, sub-array) hasa different analog beamforming direction, UEs distributed to a widerarea can transmit data at the same time in a corresponding subframe(SF).

As shown in FIG. 6b , two of four antenna ports are used by a UE1 in aregion 1 for PDSCH transmission, and the remaining two thereof is usedby a UE2 in a region 2 for PDSCH transmission.

Furthermore, FIG. 6b shows an example in which a PDSCH 1 transmitted tothe UE1 and a PDSCH 2 transmitted to the UE2 has been spatial-divisionmultiplexed (SDM).

In contrast, as in FIG. 6c , the PDSCH 1 transmitted to the UE1 and thePDSCH 2 transmitted to the UE2 may be frequency-division multiplexed(FDM) and transmitted.

From among a method of providing service to one region using all antennaports and a method of dividing antenna ports and serving several regionsat the same time, a preferred method may be different depending on arank and MCS served to a UE in order to maximize cell throughput.

Furthermore, a preferred method is different depending on the amount ofdata to be transmitted to each UE.

An eNB calculates a cell throughput or scheduling metric which may beobtained when one region is served using all antenna ports, andcalculates a cell throughput or scheduling metric which may be obtainedwhen antenna ports are divided and two regions are served.

An eNB selects the final transmission method by comparing the cellthroughputs or scheduling metrics which may be obtained through the twomethods.

As a result, the number of antenna ports participating in PDSCHtransmission in an SF-by-SF is different.

An eNB calculates the transmission MCS of a PDSCH according to thenumber of antenna ports, and requires suitable CSI feedback from a UE inorder to incorporate the CSI feedback into a scheduling algorithm.

CSI Feedback

In the 3GPP LTE (-A) system, it has been defined that a UE reportschannel state information (CSI) to a BS.

In this case, the channel state information (CSI) generally refers toinformation which may indicate the quality of a radio channel (or alsocalled a “link”) formed between the UE and an antenna port.

For example, a rank indicator (RI), a precoding matrix indicator (PMI),or a channel quality indicator (CQI) corresponds to the information.

In this case, the RI indicates rank information of a channel. This meansthe number of streams received by a UE through the same time-frequencyresource. The value is determined by long-term fading of a channel, andis fed back from a UE to a BS with a longer period than the PMI or CQI.

The PMI is a value into which channel spatial characteristics have beenincorporated, and indicates a precoding index preferred by a UE based onmetric, such as an SINR.

The CQI is a value indicating the intensity of a channel. In general,the CQI means a received SINR which may be obtained when a BS uses aPMI.

In the 3GPP LTE (-A) system, a BS may configure multiple CSI processesfor a UE, and may receive reporting for CSI for each process.

In this case, the CSI process is configured with a CSI-RS for specifyingsignal quality from the BS and a CSI-interference measurement (CSI-IM)resource for interference measurement.

Tx-Rx Beam Association

A network may transmit a known signal (e.g., a measurement referencesignal (MRS), a beam reference signal (BRS), or a beamformed channelstate information reference signal (CSI-RS) to which each beam has beenapplied in order for a UE to perform measurement on beams to be used ina corresponding cell (or may be used by an eNB), which is hereinaftergenerally called a “BRS”, for convenience of description)aperiodically/periodically.

Furthermore, a UE may select an eNB Tx beam suitable for the UE throughthe measurement of a BRS.

If up to the Rx beam of a UE is taken into consideration, the UE mayperform measurement using different Rx beams, and may select a beamcombination(s) by taking into consideration the Tx beam of an eNB andthe Rx beam of the UE.

After such a process is performed, the Tx-Rx beam association of the eNBand the UE may be determined explicitly or implicitly.

(1) Network Decision Based Beam Association

A network may indicate that a UE reports a higher XTx-Rx beamcombination as a measurement result with respect to the UE. In thiscase, the number of reported beam combinations may be pre-defined or maybe signaled by the network (through high layer signaling) or all of beamcombinations in which the measurement result exceeds a specificthreshold may be reported.

In this case, the specific threshold may be pre-defined or may besignaled by the network. If each UE has different decoding performance,a category may be defined by taking into consideration the decodingperformance of the UE, and a threshold for each category may be defined.

Furthermore, reporting on a beam combination may be performed by theindication of a network periodically and/or aperiodically.Alternatively, if a previous report result and a current measurementresult vary by a given level or higher, event-triggered reporting may beperformed. In this case, the given level may be pre-defined or may besignaled by a network (through high layer signaling).

A UE may report (one or a plurality of) beam associations determined bythe above-described method. If a plurality of beam indices is reported,priority may be assigned to each beam. For example, the beam indices maybe reported so that they are interpreted in a form, such as the first(1^(st)) preferred beam and the second (2^(nd)) preferred beam.

(2) UE Decision Based Beam Association

In the UE decision based beam association, the preferred beam reportingof a UE may be performed using the same method as the above-describedexplicit beam association.

Rx Beam Assumption for the Measurement

Additionally, the best beam(s) reported by a UE may be a measurementresult when one Rx beam is assumed or may be a measurement result when aplurality of Rx beams is assumed. The assumption of an Rx beam may beconfigured by a network.

For example, if a network has indicated that three measurement resultsshould be reported assuming one Rx beam, a UE may perform measurementusing all Rx beams, may select the best (eNB) Tx beam of the measurementresults, and may report the 1^(st), 2^(nd), 3^(rd) best results amongmeasurement results according to an Rx beam used for a corresponding Txbeam measurement.

Furthermore, a reported measurement result may be limited to exceed aspecific threshold. For example, if a beam having a measurement value(may be pre-defined or set by a network) exceeding a specific threshold,among the 1^(st), 2^(nd), 3^(rd) best beams measured by a UE using aspecific Rx beam, is only the 1st best beam, the UE may report only the1^(st) best beam to a BS.

Quasi Co-Location (QCL)

A method of demodulating, by a UE, data (e.g., PDSCH) as a UE-specificRS, such as a specific DMRS, when the UE receives the data is taken intoconsideration. Such a DMRS is transmitted with respect to only ascheduled RB(s) of a corresponding PDSCH and is transmitted for only atime period in which a scheduled PDSCH is transmitted. Accordingly,there may be a limit to reception performance in performing channelestimation using only a corresponding DMRS itself.

For example, in performing channel estimation, an estimation value of amajor large-scale parameter (LSP) of a radio channel is necessary. DMRSdensity may be insufficient in obtaining the estimation value using onlya DMRS present in a time/frequency domain in which a scheduled PDSCH istransmitted.

Accordingly, in order to support such an implementation of a UE, LTE-Asupports methods of defining the following quasi co-locationsignaling/assumption/behaviors between RS ports andconfiguring/operating a UE based on the quasi co-locationsignaling/assumption/behavior.

That is, if the large-scale characteristic of a channel in which asymbol on one antenna port is transmitted can be deduced from a channelin which a symbol on a different antenna port is transmitted, the twoantenna ports are said to have been quasi co-located (QCL).

In this case, the large-scale characteristic includes one or more ofdelay spread, Doppler spread, a Doppler shift, an average gain or anaverage delay.

Furthermore, a UE may assume the antenna ports 0 to 3, and an antennaport for the primary/secondary sync signal of a serving cell has beenQCLed with a Doppler shift and average delay.

Physical Downlink Shared Channel (PDSCH) Resource Mapping Parameters

A UE configured with the transmission mode 10 for a given serving cellmay be configured up to 4 parameter sets by higher layer signaling inorder to decode a PDSCH according to a detected PDCCH/EPDCCH having DCIformat 2D intended by the UE and the given serving cell. In order todetermine PDSCH RE mapping and if the UE has been configured as a Type BQCL type, the UE will use a parameter configured based on a value of a“PDSCH RE Mapping and Quasi-Co-Location indicator” field in thePDCCH/EPDCCH having the DCI format 2D in order to determine a PDSCHantenna port QCL.

In the case of a PDSCH not having a corresponding PDCCH/EPDCCH, the UEwill use a parameter set indicated in a PDCCH/EPDCCH having a DCI format2D corresponding to associated SPS activation in order to determine thePDSCH RE mapping and the PDSCH antenna port QCL.

Table 5 shows PDSCH RE mapping and Quasi-Co-Location Indicator fields inthe DCI format 2D.

TABLE 5 Value of “PDSCH RE Mapping and Quasi-Co- Location Indicator”field Description “00” Parameter set 1 configured by higher layers “01”Parameter set 2 configured by higher layers “10” Parameter set 3configured by higher layers “11” Parameter set 4 configured by higherlayers

The following parameters for determining the PDSCH RE mapping and thePDSCH antenna port QCL are configured through higher layer signaling foreach parameter set:

-   -   crs-PortsCount-r11    -   crs-FreqShift-r11    -   mbsfn-SubframeConfigList-r11    -   csi-RS-ConfigZPId-r11    -   pdsch-Start-r11    -   qcl-CSI-RS-ConfigNZPId-r11    -   If a UE is configured as a higher layer parameter eMIMO-Type for        a TDD serving cell, zeroTxPowerCSI-RS2-r12

Antenna Port QCL for PDSCH

A UE configured as the transmission modes 8-10 of a serving cell mayassume that the antenna ports 7-14 of the serving cell are QCL with agiven subframe with respect to delay spread, Doppler spread, a Dopplershift, an average gain and average delay.

A UE configured as the transmission modes 1-9 of a serving cell mayassume that the antenna ports 0-3, 5, 7-30 of the serving cell are QCLwith respect to Doppler shift, Doppler spread, average delay, and delayspread.

A UE configured as the transmission mode 10 of a serving cell isconfigured as one of 2 QCL types for the serving cell according to ahigher layer parameter QCL operation in order to decode a PDSCH using atransmission method related to the antenna ports 7-14:

-   -   Type A: a UE may assume that the antenna ports 0-3, 7-30 of a        serving cell are QCL with respect to delay spread, Doppler        spread, Doppler shift, and average delay.    -   Type B: a UE may assume that the antenna ports 15-30,        corresponding to a CSI-RS resource configuration identified by a        higher layer parameter qcl-CSI-RS-ConfigNZPId-r11, and the        antenna ports 7-14 associated with a PDSCH are QCL with respect        to Doppler shift, Doppler spread, average delay, and delay        spread.

In the case of an LAA Scell, a UE does not expect that the LAA Scellwill be configured as a QCL type B.

Channel-State Information-Reference Signal (CSI-RS) Definition

With respect to a serving cell and a UE configured as the transmissionmode 9 and not configured as a higher layer parameter eMIMO-Type, the UEmay be configured as one CSI-RS resource configuration.

With respect to a serving cell and a UE which has been configured as thetransmission mode 9 and configured as a higher layer parametereMIMO-Type and in which eMIMO-Type has been set as “Class A”, the UE maybe configured as one CSI-RS resource configuration.

With respect to a serving cell and a UE which has been configured as thetransmission mode 9 and configured as a higher layer parametereMIMO-Type and in which eMIMO-Type has been set as “Class B”, the UE maybe configured as one or more CSI-RS resource configuration.

With respect to a serving cell and a UE configured as the transmissionmode 10, the UE may be configured as one or more CSI-RS resourceconfiguration(s). The following parameters whose non-zero transmissionpower needs to be assumed by a UE with respect to a CSI-RS is configuredthrough higher layer signaling for each CSI-RS resource configuration:

-   -   When a UE is configured as the transmission mode 10, a CSI-RS        resource configuration identity    -   The number of CSI-RS ports    -   CSI RS configuration    -   CSI RS subframe configuration I_(CSI-RS)    -   If a UE has been configured as the transmission mode 9, a UE        assumption for reference PDSCH transmission power P_(c) for CSI        feedback    -   If a UE has been configured as the transmission mode 10, a UE        assumption for reference PDSCH transmission power P_(c) for CSI        feedback with respect to each CSI process    -   If CSI subframe sets C_(CSI,0) and C_(CSI,1) have been        configured as higher layer signaling with respect to one CSI        process, P_(c) is configured with respect to each CSI subframe        set of a corresponding CSI process.    -   Pseudo-random sequence generator parameter n_(ID)    -   If a UE is configured as a higher layer parameter eMIMO-Type and        the eMIMO-Type is set as “Class A” with respect to a CSI        process, a CDM type parameter.    -   If a UE has been configured as the transmission mode 10, a UE        assumption of a higher layer parameter qcl-CRS-Info-r11CRS for        the QCL type B, a CRS antenna port and CSI-RS antenna ports        having the following parameters:    -   qcl-ScramblingIdentity-r11.    -   crs-PortsCount-r11.    -   mbsfn-SubframeConfigList-r11.

P_(c) □is an assumed ratio of a PDSCH EPRE to a CSI-RS EPRE when a UEderives CSI feedback and takes a value of a [−8, 15] dB range as a 1-dBstep size.

In this case, the PDSCH EPRE corresponds to symbols in which the ratioof the PDSCH EPRE and cell a specific RS EPRE is indicated as ρ_(A).

A UE does not expect a configuration of a CSI-RS and a PMCH in the samesubframe of a serving cell.

With respect to a frame structure type 2 serving cell and 4 CRS ports, aUE does not expect that it will receive a CSI-RS configuration indexbelonging to sets [20-31] for a normal CP case or sets [16-27] for anextended CP case.

A UE may assume that the CSI-RS antenna port of a CSI-RS resourceconfiguration is QCL with respect to delay spread, Doppler spread,Doppler shift, average gain, and average delay.

A UE configured as the transmission mode 10 and the QCL type B mayassume that the antenna ports 0 to 3, associated with qcl-CRS-Info-r11corresponding to a CSI-RS resource configuration, and the antenna ports15 to 30 corresponding to a CSI-RS resource configuration are QCL withrespect to Doppler shift and Doppler spread.

A UE which has been configured as the transmission mode 10 andconfigured as a higher layer parameter eMIMO-Type and in whicheMIMO-Type is set as “Class B” and the number of configured CSIresources is one greater than one CSI process and which has the QCL typeB does not expect that it will receive a CSI-RS resource configurationfor a CSI process having a different value of a higher layer parameterqcl-CRS-Info-r11.

A BL/CE UE configured as CEModeA or CEModeB does not expect that it willbe configured as a non-zero transmission power CSI-RS.

Assumptions Independent of Physical Channel

A UE does not assume that two antenna ports are QCL, unless describedotherwise.

A UE may assume that the antenna ports 0 to 3 of a serving cell are QCLwith respect to delay spread, Doppler spread, Doppler shift, averagegain, and average delay.

For the purpose of discovery signal-based measurement, a UE does notassume the presence of a different signal or physical channel other thana discovery signal.

If a UE supports discoverySignalsInDeactSCell-r12, the UE has beenconfigured as discovery signal-based RRM measurement in a carrierfrequency that may be applied to a secondary cell in the same carrierfrequency, the secondary cell has been deactivated, and the UE has notbeen configured by a higher layer in order to receive an MBMS in thesecondary cell, an activation command for a PSS, SSS, PBCH, CRS, PCFICH,PDSCH, PDCCH, EPDCCH, PHICH, DMRS and a CSI-RS other than discoverysignal transmission is not transmitted by the secondary cell up to asubframe received with respect to the secondary cell.

In the above-described operation, for example, in the case of a UEconfigured as the QCL Type B, in order to receive help for the channelestimation of a DMRS transmitted along with a scheduled PDSCH, the UE islimited to use LSPs estimated from a specific QCLed CSI-RS resourceindicated in corresponding scheduling DCI.

In the new RAT (NR) environment taken into consideration in thisspecification, however, an aperiodic CSI-RS transmission method in theaspect that a CSI-RS itself is transmitted only when it deviates from aconventional periodic form is taken into consideration. Accordingly,there is a problem in that RS density to be use as a QCL CSI-RS may besufficiently insufficient compared to a conventional technology.

At least one of the followings may be defined/configured as QCLparameters taken into consideration in the NR environment:

-   -   Delay spread    -   Doppler spread    -   Doppler shift    -   Average gain    -   Average delay    -   Average angle (AA)

This may mean that, for example, an Rx beam direction (and/or Rx beamwidth/sweeping degree) when a transmission signal from other antennaport(s) is received based on an AA estimated from a specific antennaport(s) is configured to be the same or similar (in association withthis) and reception processing is possible (meaning that receptionperformance when an operation is performed as described above isguaranteed to be a specific level or more) between antenna ports whoseQCL is guaranteed in the AA viewpoint.

The AA may also be represented as a name, such as an “(almost) dominantarrival angle”, for example.

As a result, if a specific dominant (arrival) angle S of a signalmeasured from a specific antenna port is present, a specific dominant(arrival) angle of a signal measured from another antenna port capableof QCL assumption with the specific dominant (arrival) angle S may havea meaning that it is “almost” similar to the S.

That is, if such a QCL assumption is possible, this means that areceiver can use/apply an AA, estimated from a specific indicated QCLedRS/SS, to reception processing “almost” without any change. Accordingly,there is an advantage in that the efficient implementation/operation ofa receiver are made possible.

Angular Spread (AS):

QCL in an AS aspect between two antenna ports means that an AS estimatedfrom one port may be derived or estimated or applied from an ASestimated from another port.

In this case, the AS may be separately defined for each specificdimension as an azimuth and/or a zenith AS or may be defined together.Furthermore, in the departure and/or arrival aspect, the AS may bedefined separately or together.

This may mean that, for example, an Rx beam width/sweeping degree(and/or Rx beam direction) when a transmission signal from other antennaport(s) is received based on an AA estimated from a specific antennaport(s) is configured to be the same or similar (in association withthis) and reception processing is possible (meaning that receptionperformance when an operation is performed as described above isguaranteed to be a specific level or more) between antenna ports whoseQCL is guaranteed in the AA viewpoint.

That is, if the AA has a characteristic meaning an average and the(most) effective/dominant beam direction, the AS may be interpreted as aparameter regarding that how much is the beam direction spread andreceived by a radiator distribution (based on/with reference to the AA).

The New RAT (NR) has an advantage in that it can obtain a beamforminggain using a narrow analog beam, but has a disadvantage in that it cansupport only a UE present within a specific direction per time instance(e.g., symbol, slot, subframe).

The same problem is present in terms of a receiver that receives asignal in addition to a transmitter that transmits the signal.Accordingly, performance degradation may occur if beam associationbetween Tx and Rx is inaccurate.

FIG. 7 shows an example of a Tx-Rx beam configuration between an eNB anda UE to which a method proposed in this specification may be applied.

As shown in FIG. 7, it is assumed that an eNB can configure (M+1) Tx(analog) beams (Tx beam #0, . . . , Tx beam #M) and a UE can configure(N+1) Rx (analog) beams (Rx beam #0, . . . , Rx beam #N).

In FIG. 7, in Tx-Rx beam setting between the eNB and the UE, receptionperformance may be increased when the UE receives a signal based on theTx beam #2 of the eNB using the Rx beam #2.

In contrast, regarding a signal transmitted by the Tx beam #2, receptionperformance is reduced or not detected in an Rx beam except the Rx beam#2.

Accordingly, if the eNB and the UE transmit and receive PDCCHs usingonly a (Tx-Rx) beam combination having the best reception performancethrough measurement, the UE may not detect the PDCCH due to a suddenchange in the channel environment, such as UE mobility, rotation, orblockage.

The eNB may be aware of such a situation using an implicit or explicitmethod as in the following four examples.

That is, the following four examples show examples in which the eNB canbe aware of the PDCCH detection failure of the UE using an implicit orexplicit method.

The first is the case where the eNB has transmitted a DL grant to theUE, but has not received acknowledgement (Ack) or non-acknowledgement(Nack) from the corresponding UE.

The second is the case where the eNB has transmitted an UL grant to aUE, but has not received UL data from the corresponding UE.

The third is the case where if channel reciprocity is established, ULTx-Rx beam quality measurement is possible through UL RS measurement andDL Tx-Rx beam quality can be aware through the UL Tx-Rx beam qualitymeasurement.

The fourth is the case where the eNB can be aware of the current DLTx-Rx beam quality through the aperiodic or periodic beam reporting (ofthe UE).

Accordingly, this specification proposes a method of transmitting andreceiving robust PDCCHs in order to solve the PDCCH detection failure ofa UE attributable to a sudden change in the channel environment.

First, a method of indicating QCL regarding a new spatial parameter forPDCCH reception proposed in this specification is described.

In this specification, as described above, it is assumed that a Tx-Rxbeam association has been previously performed and a network (NW) isaware of information on the best beams of a corresponding UE through aUE beam report.

The NW may previously signal to each UE for a subframe set in which eachUE has to perform blind decoding on a control channel (through a masterinformation block (MIB), a system information block (SIB) or RRCsignaling) based on the beam report of the UE.

For the Rx beam configuration of the UE for PDCCH decoding in thesubframe set, the NW may configure QCL for a new spatial parameter(e.g., dominant arrival angle) and notify the UE of the QCL as describedabove.

In this case, the new spatial parameter may mean information indicatingthat the resource of a DMRS for the PDCCH decoding has been QCLed withthe resource of a BRS.

That is, the new spatial parameter may be interpreted as informationindicating the resource of a DMRS for the PDCCH decoding QCLed with theresource of a BRS (antenna port, etc.) or information indicating theresource of a BRS QCLed with the resource of a DMRS for the PDCCHdecoding.

For example, the UE may decode the PDCCH in a corresponding BRS Rx beamdirection based on information (i.e., a new spatial parameter)indicating that a specific BRS (or MRS or CSI-RS) and a DMRS for PDCCHdemodulation have been QCLed in a dominant arrival angle (DAA)viewpoint.

That is, the new spatial parameter may be a parameter that enables an Rxbeam (of the UE) for the PDCCH decoding to be aware through the Rx beamof a BRS.

Accordingly, the UE may decode the PDCCH through the Rx beam indicatedby the new spatial parameter (or having a QCL relation with the UE Rxbeam for the BRS).

An NW may define a plurality of control symbols within one subframe, andmay broadcast the control symbols within a cell or may indicate thenumber of corresponding control symbols with respect to a UE throughhigher layer signaling (or may notify the UE of the number of controlsymbols through a physical channel as in a physical control formatindicator channel (PCFICH) in LTE).

In other words, the NW may signal the number of control symbols persubframe in a given period or aperiodically.

This may mean that the NW allocates a different number of controlsymbols for each subframe (set).

If a variation for a channel environment with a corresponding UE is lowand a reception signal in the UE is strong, a NW may indicate only onecontrol symbol with respect to the UE.

In this case, a PDCCH may be transmitted only in the first symbol of asubframe (set), and a PDSCH may be transmitted from the second symbol.

In this case, the UE may perform a blind decoding operation on the PDCCHby applying a different Rx beam or the same Rx beam for each controlsymbol.

As another meaning, it may be interpreted that if the UE performs binddecoding by applying a different Rx beam, a search space in which thedifferent Rx beam is assumed for each control symbol is defined.

A method of receiving, by a UE, a PDCCH and/or a PDSCH is describedbelow through various embodiments.

First, (1) a method of blind-detecting a PDCCH using multi-Rx beams(first embodiment) and (2) a method of blind-detecting a PDCCH using asingle Rx beam (second embodiment) are described below.

The first embodiment, that is, the method of blind-detecting a PDCCHusing multi-Rx beams, may be divided into a method 1 and a method 2depending on whether QCL is present for the above new spatial parameter(or whether QCL is configured for the new spatial parameter).

QCL for the new spatial parameter may be simply called beam indication(for a PDCCH and/or a PDSCH).

A beam indication configuration method as a specific time instancetiming unit (e.g., for each control symbol) described in the followingembodiments is an example, and is not limited thereto. A beam indicationconfiguration proposed in this specification may be provided for eachseparate control resource SET (CORESET) and/or through the medium ofspecific higher layer signaling, such as a PDCCH monitoringconfiguration.

In this case, the CORESET may include N_(RB) ^(CORESET) resource blocksin a frequency domain and N_(symb) ^(CORESET) ∈{1,2,3} symbols in a timedomain.

The N_(RB) ^(CORESET) and the N_(symb) ^(CORESET) are given by ahigher-layer parameter.

That is, the following methods may be construed as being applied to aspecific control symbol and/or a specific slot number in which a PDCCHis transmitted based on a beam indication configuration using specifichigher layer signaling as a medium.

For example, beam indication for a CORESET #1 and beam indication for aCORESET #2 may be differently configured, and a PDCCH may be receivedover two (control) symbols at specific slot timing.

In this case, if a PDCCH corresponding to the CORESET #1 is received inthe first control symbol and a PDCCH corresponding to the CORESET #2 isreceived in the second control symbol, at least one operation or methodproposed in this specification may be applied based on a separate (orindependent) beam indication configuration for each control symbol.

First Embodiment

(Method 1)

The method 1 relates to a method of blind-detecting, by a UE, a PDCCHusing multi-Rx beams if beam indication is not present (or if QCL for anew spatial parameter is not present).

An operation of a UE to blind-detect (or blind-decode) a PDCCH usingmulti-Rx beams may be represented as a “first operation mode” or amulti-Rx beam PDCCH blind detection mode.”

In other words, the method 1 operates in a default mode when a UE doesnot have indication with respect to an Rx beam for PDCCH blind decoding(or blind detection).

As described in the “Tx-Rx beam association” part, a UE may select asuitable Tx-Rx beam combination through the measurement of a BRS.

In this process, the priority of a Tx-Rx beam combination may bedetermined based on the measurement result of a BRS.

The UE may report higher X Tx-Rx beam combinations (or corresponding Txbeam information), indicated from an NW, to the NW.

When the UE performs PDCCH blind decoding in a specific subframe set, ifindication for a separate Rx beam is not present for PDCCH reception,the UE monitors or blind-decodes a PDCCH using an Rx beam correspondingto the sequence in which the Tx-Rx beam combinations (or correspondingTx beam information) are reported for each control symbol.

In other words, the UE configures corresponding Rx beams sequentiallybased on the (report) priority of the Tx-Rx beam combinations, andblind-decodes a PDCCH control symbol.

That is, an operation of a UE in the default mode may mean that the UEsequentially configures corresponding Rx beams based on the reportpriority of Tx-Rx beam combinations and blind-detects a PDCCH for eachcontrol symbol.

(Method 2)

Next, the method 2 relates to a method of blind-detecting, by a UE, aPDCCH using multi-Rx beams if beam indication is present (or if QCL fora new spatial parameter is present).

That is, unlike in the method 1, in the method 2, an NW configures a newspatial parameter (e.g., dominant arrival angle) or QCL for the beamindication with respect to the Rx beam configuration of a UE for PDCCHdecoding in a specific subframe set, and notifies the UE of the newspatial parameter or QCL. The UE blind-detects the PDCCH.

In this case, the UE may perform blind detection on the PDCCH byapplying a different Rx beam through a different QCL configuration foreach control symbol.

Alternatively, if the UE receives a different beams indicationconfiguration for each CORESET through higher layer signaling, when aPDCCH corresponding to each CORESET is received for each differentspecific timing (e.g., for each control symbol or for each slot number),the UE may perform blind decoding (or detection) on the PDCCH byapplying a different RX beam for each timing.

As described above, In relation to a different beam indicationconfiguration for each CORESET, the concept that a different beam foreach specific timing is applied to a specific signal (or a specificchannel) may be identically applied to embodiments to be describedlater.

FIG. 8 shows an example in which QCL for a new spatial parameter hasbeen configured for each control symbol, which is proposed in thisspecification.

From FIG. 8, it may be seen that 2 symbols (first and second symbols)have been allocated to a control symbol for PDCCH reception.

A UE may independently configure search spaces for different Rx beamsusing QCL 1 (e.g., dominant arrival angle 1) information and QCL 2(e.g., dominant arrival angle 2) information in respective controlsymbols, and may perform blind decoding on a PDCCH.

The QCL 1 and the QCL 2 may be transmitted from an NW to the UE throughL1 signaling or L2 signaling dynamically (subframe in which a PDCCH ismonitored) in a previous X-th subframe.

Alternatively, the QCL 1 and QCL 2 may be transmitted through L3signaling semi-statically.

In this case, the first control symbol may be defined as a controlsymbol for a primary PDCCH, and the second control symbol may be definedas a control symbol for a secondary PDCCH.

In this case, the primary and the secondary may mean the priority of asearch space for the blind decoding of the UE.

In FIG. 8, the primary PDCCH may be decoded through the DMRS of thefirst symbol configured as QCL 1, and the secondary PDCCH may be decodedthrough the DMRS of the second symbol configured as QCL 2.

Accordingly, the UE performs independent DMRS demodulation on eachsearch space for the decoding of each PDCCH.

For example, the primary PDCCH may be transmitted from an eNB to acorresponding UE using the best Tx beam. For corresponding Rx beamsetting, QCL 1 is configured. In contrast, the secondary PDCCH is forPDCCH reception more robust than the primary PDCCH, and may betransmitted using the second best Tx beam (or multiple best Tx beams).For corresponding Rx beam setting, QCL 2 may be configured.

In other words, the Tx beam of the PDCCH may be changed based on thescheduling of the eNB. The Rx beam of the UE for the PDCCH may beconfigured or determined through a QCL configuration.

Furthermore, a MIMO scheme more robust than that of the primary PDCCHmay be used for the secondary PDCCH.

That is, the method 2 has an advantage in that the PDCCH resourceoperation of an eNB may be more free compared to the method because(PDCCH) Rx beam setting is possible through QCL.

Additionally, in the method 2, a primary PDCCH may be not detectedthrough the best Tx-Rx beam due to blockage, and only the decoding of asecondary PDCCH may be possible.

In this case, a UE may determine that the best Tx-Rx beam is not goodand may override the Rx beam of a secondary PDCCH and use it as a PDSCHRx beam.

In other words, the UE may share a DMRS for the secondary PDCCH for theuse of a DMRS for PDSCH reception.

In contrast, in the method 2, if a UE has detected a primary PDCCH, itmay override the Rx beam of a primary PDCCH and use it as a PDSCH Rxbeam.

This means that a DMRS for the primary PDCCH may be used for a DMRS forPDSCH reception.

In the method 1 and the method 2, all configured DCI information of acorresponding UE may be received in the primary PDCCH.

If a UE receives all configured DCI information in a primary PDCCH froman eNB, the UE may omit the blind decoding of a secondary PDCCH. Thatis, through the process, the complexity of blind decoding by a UE for aPDCCH can be reduced.

Second Embodiment

The second embodiment relates to a method of blind-detecting, by a UE, aPDCCH using a single Rx beam if beam indication is present (or if QCLfor a new spatial parameter is present).

In this case, an operation for the UE to blind-detect the PDCCH using asingle Rx beam may be represented as a “second operation mode” or a“single Rx beam PDCCH blind detection mode.”

A UE may perform a PDCCH reception operation by applying the same Rxbeam through the same QCL configuration for each control symbol.

A UE may share DMRS demodulation information of each control symbol inorder to decide the search space of each control symbol due to the sameQCL configuration.

Third Embodiment

The third embodiment relates to a method of searching, by a UE, part ofa PDCCH search space corresponding to an indicated (by NW) Rx beam.

With respect to an indicated Rx beam, a UE may perform PDCCH blinddecoding on part of the search space through search space mapping.

In this case, the indicated Rx beam and the search space mapping may bepreviously configured in the corresponding UE through higher layersignaling (e.g., RRC signaling).

That is, the second embodiment is a method of decoding, by a UE, thesearch space of all PDCCHs. In contrast, the third embodiment is amethod of decoding only the search space of part of a PDCCH searchspace, and can reduce a load of a UE for PDCCH decoding. As a result,power of the UE can be reduced.

The above-described new spatial parameter is described more specificallybelow.

The new spatial parameter may be called QCL indication or beamindication.

That is, the new spatial parameter may mean a parameter providingnotification that the resource of a BRS and a PDCCH and/or PDSCHresource have been QCLed.

As described above, for the Rx beam configuration of a UE for PDCCHdecoding, an NW may transmit, to the UE, information (QCL indication ornew spatial parameter or beam indication) indicating that a specific BRS(e.g., a mobility RS (MRS), a synchronize signal (SS) block, a CSI-RS)and a DMRS for PDCCH demodulation have been QCLed spatially partially(e.g., a dominant arrival angle (DAA), the mean of arrival angle). TheUE may decode the PDCCH in a BRS Rx beam direction based on thecorresponding information.

The NW may transmit, to the UE, QCL indication (or beam indication forPDCCH reception) dynamically in a previous X-th subframe (in which thePDCCH is monitored based on corresponding QCL indication) through L1signaling or L2 signaling or may transmit the QCL indication through L3signaling semi-statically.

(1) If the QCL indication is transmitted through only L1 signaling(e.g., DCI), there is an advantage in that an eNB can schedule DCIdynamically, but there is a disadvantage in that the payload size of DCIgreatly increases.

(2) If the QCL indication is transmitted through only L2 signaling (MACCE), a problem in that the size of DCI payload increases can be solved,but there is a disadvantage in that latency is relatively increasedcompared to the L1 signaling.

(3) If the QCL indication is transmitted through only L3 signaling (RRCmessage), there is no restriction to the size of DCI payload, but thereis a disadvantage in that there is a limit to the PDCCH scheduling of aneNB because the RRC message is transmitted in a relatively long period.

Accordingly, in order to properly take the advantages and disadvantagesof the (1) to (3), an NW may combine the following three cases andhierarchically signal to a UE for QCL indication.

For example, an NW may configure N beam sets (or beam groups) for thePDCCH reception of a UE, and may notify the UE that a PDCCH Rx beam hasto be configured using which beam set for each slot (or subframe)through L2 signaling or L3 signaling.

More specifically, the NW may designate the period of a slot that needsto be received for each beam set and a multiple of a slot number in sucha manner that priority is assigned to N beam sets, the first beam set isconfigured every slot number of a multiple of 4, and the second beam setis configured every slot number of a multiple of 7.

Such a method can be naturally expanded to a specific pattern method ineach beam set. If beam sets that need to be received in the same slotoverlap (or are to overlap), a UE may configure a beam set based onpriority or a pre-designated sequence.

Such a beam set may be beam information corresponding to a specific BRSor BRS set.

If multiple beam sets are configured in a slot in which a PDCCH isreceived, an eNB may dynamically indicate that a corresponding PDCCHshould be received in which beam set through L1 signaling or L2signaling with respect to a UE.

Alternatively, the eNB may indicate that a corresponding PDCCH should bereceived using which beam within a specific beam set configured in aspecific slot with respect to the UE.

A detailed method of configuring N beam sets (or beam groups) for PDCCHreception may be described as in the following options.

(Option 1)

Option 1 is a method of configuring N beam sets (or beam groups) forPDCCH reception based on the beam report of a UE (without separate eNBsignaling).

For example, if a UE reports M-beam information, an NW may map M beamsto N beam sets using M-beam direction information and RSRP.

For example, beam information having the greatest RSRP may be mapped tothe first beam set, and the remaining (M−1) beams may be mapped to thesecond beam set.

The mapping method may be performed in various ways using a methodpreviously agreed between an eNB and a UE.

(Option 2)

Option 2 is a method of configuring, by an eNB, a beam set by indicatingthe activation/deactivation of N beam sets, configured through L3signaling (RRC message), through L2 signaling (MAC-CE).

In this case, a UE does not receive a PDCCH or may receive a PDCCHthrough an alternate beam set by default (or according to pre-designatedpriority) in a slot corresponding to a deactivated beam set.

(Option 3)

An eNB may update or substitute a beam within a beam set through L2signaling (MAC-CE) or L3 signaling (RRC message) with respect to eachbeam set.

For example, it is assumed that two beam sets are defined and the twobeam sets are {#3, #8} and {#8, #4}.

Beam information of the first beam set may be updated with #11 oranother piece of beam information may be added or the deletion of theexisting beam information may be indicated through L2 signaling or L3signaling with respect to a UE having the above beam information.

(Option 4)

An eNB may indicate a specific beam in a beam set of a correspondingslot through L1 signaling (DCI) with respect to a UE.

For example, if information on 4 beams of {#2, #4, #9, #5} is includedin the first beam set, an eNB may dynamically determine a specific beamwithin the beam set using 2 bits.

For example, the 2 bits may be defined as “00” (first beam), “01”(second beam), “10” (third beam), and “11” (fourth beam).

If only one piece of beam information is included in the beam set of thecorresponding slot, the DCI signaling of an NW may be omitted. Ifseparate signaling is not present, a UE may receive a PDCCH in the firstbeam according to pre-designated priority within the beam set.

If the UE receives PDCCHs in several beam directions at the same time,an eNB may indicate the signaling in a bitmap form.

For example, if a bitmap is [1 0 0 1], this may mean that a PDCCH isreceived in a corresponding slot through the first Rx beam, the fourthRx beam.

Furthermore, the L1 signaling may be transmitted in the PDCCH of an X-th(>=1) slot or subframe prior to (PDCCH reception).

Some of or all the above-described options (Option 1 to 4) may beapplied at the same time, and beam indication (or QCL indication) forPDCCH reception may be configured as various combinations.

Furthermore, as described above, beam information within a beam setindicates a BRS (e.g., a mobility RS (MRS), a synchronize signal (SS)block or a CSI-RS). Beam information, such as a beam #3 or #6, isindicated for convenience of understanding, and may indicate theresource index, resource index/antenna port index or ID of each RS.

Option 1 is described more specifically.

As described above, an eNB may update or designate beam information of Nbeam sets (or beam pair link) for the PDCCH reception of a UE based onthe beam reporting of the UE.

In this case, an NW may notify the UE of the update or modification ofthe beam information based on the beam reporting of the UE throughseparate signaling in order to confirm the update or modification.

In this case, a message for the confirmation may be transmitted to theUE through DCI or a MAC-CE.

Alternatively, the eNB may add 1 bit for the confirmation to the DCIindicating each beam set (or beam pair link), and may notify the UE ofconfirmation information regarding whether each beam set has beenupdated.

For example, there are N beam sets in each of which one piece of beaminformation may be allocated to each beam set, and reported beaminformation may be designated and updated in each beam set through M(<=N) beam reporting.

In this case, the eNB may provide notification that all the beam setshave been updated based on the M beam reporting through the DCI orMAC-CE of a corresponding confirmation message or may providenotification that a corresponding beam set is individually updated withreported beam information by adding 1 bit to DCI information fordesignating a specific beam set at the same time.

Accordingly, the UE that has received the confirmation message from theeNB may update PDCCH Rx beam information for each beam set based on thebeam-reported beam information, and may receive a PDCCH.

The following contents are additionally described in relation to theabove contents.

For beam indication for monitoring an NR-PDCCH, various signalingmethods, such as DCI signaling, MAC-CE signaling, RRC signaling,specification-transparent and/or combinations of these signalingmethods, may be taken into consideration.

The beam indication may have the same meaning as the above-described newspatial parameter or QCL indication.

First, in a given symbol/slot or NR-PDCCH time/frequency domainresource, some rules and/or configurations regarding a time/frequencydomain pattern may be used for NR-PDCCH reception.

In order to scheduling restriction from the approach method, whatcontrol beam information for the dynamic indication of a PDCCH beam maybe transmitted prior to PDCCH transmission may be taken intoconsideration.

If a plurality of candidate beams for NR-PDCCH reception is present,2-level indication based on L1 signaling or L2 signaling along with anRRC configuration may be taken into consideration because DCI-onlyindication may not be proper due to the restriction of a DCI payloadsize.

For example, the NR-PDCCH time/frequency/space region monitoringresource of each beam pair link (BPL) may be configured by RRC, and anaccurate PDCCH beam may be indicated by dynamic signaling, such as aMAC-CE or DCI signaling.

Furthermore, this may be dynamically indicated only when a BPL ischanged.

In this case, beam information of each BPL may be implicitly updatedbased on beam reporting information.

That is, a beam direction related to N BPLs may be mapped as N-beamreporting information in a given rule, such as an RSRP/CQI-basesequence.

In this case, an NW (or an eNB) may transmit, to a UE, a confirmationregarding that a reported beam is applied to each BPL.

Dynamic beam indication for an NR-PDCCH is taken into consideration, anddynamic signaling indicates one or more of the following information.

-   -   Selection of a beam within a set for each BPL    -   BPL switching    -   Beam change confirmation of each BPL for a reported beam

Table 6 is an example of the third embodiment, and is a table showing amethod of differently configuring a beam in which blind decoding isperformed for each DCI format.

TABLE 6 Rx beam #1 Rx beam #2 Rx beam #3 DCI 0 ◯ ◯ ◯ DCI 1 ◯ ◯ X DCI 2 ◯X X DCI 3 ◯ X X

A UE may be configured with a total of N Rx beams (Tx-Rx beam pair,Tx-Rx associated beam) as PDCCH Rx beams.

Table 6 shows an example when N=3, assuming that four DCI formats areconfigured as 0-3.

As in Table 6, a DCI format in which blind decoding is performed may bedifferently configured for each Rx beam (Tx-Rx beam pair, Tx-Rxassociated beam) in which a PDCCH is received.

For example, a PDCCH may be chiefly received in the Rx beam #1, and aPDCCH may be received in the Rx beam #2 and the Rx beam #3 in a longerperiod than the Rx beam #1 for the robustness of a UE.

In this case, the PDCCH decoding load of the UE for can be reduced bydecoding only the PDCCH of a given part through the Rx beam #2 and theRx beam #3.

An eNB may previously configure a DCI format for each Rx beam throughhigher layer signaling.

Furthermore, the third embodiment may be identically applied to anuplink physical uplink control channel (PUCCH).

For example, an UCI format may be differently configured for each Txbeam (or beam pair link, Tx-Rx associated beam) of a UE that transmits aPUCCH.

Fourth Embodiment

The fourth embodiment relates to a method of allocating a time gap to amulti-symbol PDCCH by taking beam switching latency into considerationand reporting the capability of a UE for the allocation, if the UEreceives a multi-symbol PDCCH through a different Rx beam (Tx-Rxassociated beam) within one slot (or subframe).

FIG. 9 is a diagram showing an example in which a time gap has beenallocated within a multi-symbol PDCCH, which is proposed in thisspecification.

As shown in FIG. 9a , a UE may receive a PDCCH through a different Rxbeam (or Tx-Rx associated beam, beam pair).

In this case, although a different Rx beam corresponds to a differentpanel or changed within one panel, beam switching may be difficultwithin the cyclic prefix (CP) of an OFDM symbol due to the latency ofhardware depending on a UE.

Accordingly, in such a situation, there may be a problem when acorresponding UE receives a multi-symbol PDCCH within one slot (orsubframe) through a different Rx beam.

In order to solve this problem, an eNB previously requests capabilityinformation for the beam switching latency of a corresponding UE fromthe corresponding UE through a higher layer message (or signaling).

Alternatively, the capability information for the beam switching latencymay be previously transmitted from the UE to the eNB through an RRCmessage.

In this case, in the case of a UE whose beam switching latency is agiven threshold or more, an eNB may allocate a time gap between PDCCHsymbols so that the corresponding UE receives a PDCCH through adifferent Rx beam, as in FIG. 9 b.

The time gap may be one piece of OFDM symbol duration or may be timeduration previously designated by taking beam switching latency intoconsideration.

In the case of a UE that receives a PDCCH through a different Rx beam,an eNB may transmit information on a time gap for the corresponding UEthrough L1 signaling or L2 signaling dynamically or through L3 signalingsemi-statically.

The fourth embodiment may be identically applied to an UL PUCCH.

For example, if a multi-symbol PUCCH is transmitted through a differentTx beam (or beam pair link, Tx-Rx associated beam), a time gap may bedefined between PUCCH symbols by taking into consideration the beamswitching latency of a UE (or eNB), and a PUCCH may be transmitted.

The contents related to the fourth embodiment are additionally describedas follows.

NR-PDCCH transmission supports robustness for beam pair link blocking.

-   -   A UE may be configured to monitor NR-PDCCHs on an M-beam pair        link at the same time.

M≥1. a maximum value of M may depend on at least a UE capability.

(The UE may select at least one beam among the M-beam pair link forNR-PDCCH reception.)

-   -   A UE may be configured to monitor an NR-PDCCH on a different        beam pair link(s) in different NR-PDCCH OFDM symbols.

(an NR-PDCCH on one beam pair link is monitored in a shorter duty cyclethat that of another beam pair link(s)).

-   -   A parameter related to UE Rx beam setting for monitoring an        NR-PDCCH on a plurality of beam pair links may be configured by        higher layer signaling or a MAC CE or is taken into        consideration in the search space design.

The start position of downlink data in a slot may be indicatedexplicitly and dynamically with respect to a UE.

This may be signaled by a UE-specific DCI and/or a “group-common PDCCH.”

For the reception of a unicast DL data channel, the indication of aspatial QCL assumption between a DL RS antenna port and the DMRS antennaport of a DL data channel is supported: information indicating an RSantenna port is indicated through a DCI (downlink grants).

This information indicates the RS antenna port QCLed with the DMRSantenna port.

The information may explicitly indicate an RS port or a resource ID ormay be implicitly obtained.

For example, the information (or QCL indication) or indication may beapplied to only a scheduled PDSCH or may be applied up to only thefollowing indication.

A candidate signaling method of beam indication for an NR-PDCCH (i.e., aconfiguration method of monitoring an NR-PDCCH) may be MAC CE signaling,RRC signaling, DCI signaling, specification transparent and/or implicitmethod or combinations of them.

Fifth Embodiment

In another embodiment, a method of indicating a PDSCH beam using DCI,which is proposed in this specification, is described.

That is, the first embodiment relates to a beam relation between acontrol channel and a data channel.

First, what a Tx/Rx beam for a DL data channel is the same as a Tx/Rxbeam for a DL control channel may be taken into consideration.

If the same beam is used for control channel and corresponding datachannel transmission, a DMRS may be shared for control channel and datachannel demodulation in order to reduce DMRS overhead. Additional beaminformation for an NR-PDSCH capable of reducing signaling overhead doesnot need to be indicated.

FIG. 10 shows an example of a control channel and in which differentbeams are used for corresponding data channel transmission to which amethod proposed in this specification may be applied.

In contrast, if a decoupling beam is permitted for a control channel anda data channel, more freedom may be provide to optimize a data beam. Forexample, a serving Tx beam for an NR-PDSCH may be sharper than a servingTx beam for an NR-PDCCH in order to improve a data throughput.

Furthermore, as shown in FIG. 10, the transmission of NR-PDSCHs from aplurality of TRPs may be permitted.

For flexible DL data transmission, NR-PDSCH beam information may bedynamically signaled through a corresponding NR-PDCCH.

In this case, a time gap may be necessary between the control channeland the data channel due to beam switching latency. Likewise, the timegap may be necessary even in FIG. 9.

Such a characteristic may depend on a UE capability regarding beamswitching latency.

That is, to define a time gap between a primary PDCCH and a second PDCCHand between a PDCCH and a PDSCH depending on the capability of a UE maybe taken into consideration.

As described above, in NR, the Rx beams (or Tx-Rx beam association, beampair link (BPL)) of a control channel and a data channel may bedifferently configured for dynamic point selection and flexible datatransmission.

To this end, NR-PDSCH beam indication may be dynamically configuredthrough DCI.

The NR-PDSCH beam indication may indicate information indicating an RSport spatially QCLed with a DMRS port for PDSCH demodulation, for Rxbeam setting.

If DCI decoding latency of an indicated beam is different from that of aPDCCH Rx beam with respect to DCI signaling for the PDSCH Rx beamsetting, a consideration for the Rx beam switching latency of a UE isnecessary for PDSCH reception.

It may assume that a corresponding eNB is aware of the decodingcapability of the UE and UE capability information regarding the beamswitching latency by previously forwarding them through a higher layersignal (RRC message, MAC-CE, etc.).

Hereinafter, a detailed method of DCI signaling for PDSCH Rx beamsetting and a corresponding operation of a UE are described below.

The number of bits of DCI signaling of for a PDSCH Rx beam configurationmay be different depending on the number of pre-configured PDSCH Rxbeams (or BPLs).

The DCI signaling may indicate a specific Rx beam within a PDSCH Rx beam(or BPL) pre-configured through RRC or a MAC-CE or may indicate that thespecific Rx beam is received as a characteristic beam pair within a beampair group configured as the Rx beam of a PDCCH.

For example, if PDSCH beam indication is defined as DCI of 2 bits, a“00” value may indicate that a PDSCH is received through apre-designated default Rx beam or a PDSCH is received through the samebeam as a PDCCH Rx beam.

A “01” value may indicate that a PDSCH is received through apre-configured secondary Rx (or secondary BPL).

“10” and “11” values may indicate that a PDSCH is received through apre-configured 3^(rd) Rx beam, 4^(th) Rx beam.

A UE operation according to such a PDSCH beam indication may be asfollows.

(1) If the PDSCH beam indication is “00” and indicates that a PDSCH isreceived through the same Rx beam as a PDCCH Rx beam

In this case, a UE may receive DL data (or PDSCH) without taking intoconsideration beam switching latency because it does not require theswitching of an Rx beam.

For example, if an OFDM symbol offset necessary between a DL grant and acorresponding PDSCH is “x” by taking into consideration DCI decodinglatency, when a UE receives the DL grant in an n-th OFDM symbol from aneNB, the UE may expect that the corresponding PDSCH is started orreceived after an (n+x)-th OFDM symbol.

Furthermore, an eNB may dynamically indicate the reception position (ortiming) of DL data through DCI. The DCI may indicate and indicate thatthe reception of the DL data is after at least the (n+x)-th OFDM symbol.

(2) If the beam indication is set as “00” and indicates that a PDSCH isreceived through a default Rx beam or is set as “01”, “10” or “11” andindicates that a PDSCH is received through an Rx beam different from aPDCCH Rx beam

An eNB previously configures the default PDSCH Rx beam through RRC or aMAC-CE, and a corresponding default PDSCH Rx beam may be different froma PDCCH Rx beam.

In response thereto, a corresponding UE receives DL data from the eNB byadditionally taking into consideration Rx beam switching latency.

For example, when an OFDM symbol offset necessary between a DL grant andcorresponding PDSCH reception is “y (y may be greater than or equal tox)” by taking into consideration DCI decoding latency and beam switchinglatency at the same time, if a UE has received the DL grant in an n-thOFDM symbol from an eNB, the UE may expect that a corresponding PDSCHstarts (or is received) after an (n+y)-th OFDM symbol.

If the OFDM symbol position (or timing) of a data reception signal inDCI is “n+r” smaller than “n+y”, the UE may neglect it and receive thePDSCH from the eNB after “n+x.”

Alternatively, the eNB may dynamically indicate the reception positionof the DL data through DCI. The DCI may indicate that the receptionposition of the DL data is limited after at least n+y.

As another method, the PDSCH beam indication may include the Rx beamindication of a subsequent slot, not a corresponding slot, by taking thebeam switching latency into consideration. For example, beam indicationfor the PDSCH reception of an (n+x)-th slot through DCI may be possiblein an n-th slot.

In this case, the “x” value is previously set through higher layersignaling. If the “X” value has been set as “0”, it may operate as thefirst embodiment.

In order to perform (or operate) flexible DL data transmission, NR-PDSCHbeam information may be dynamically signaled through an NR-PDCCH.

Furthermore, in order to support UE-side beamforming/reception, an NRneeds to aim at low overhead indication for a spatial QCL assumption.

According to an NR-PDSCH beam, it is necessary to indicate PDSCH REmapping information that may include a PDSCH start symbol. That is, insome cases, it is necessary to provide a ZP CSI-RS resource ID, a beamswitching time gap and a DCI decoding time for protecting the CSI-RS ofa neighbor beam.

Accordingly, as in the LTE spec. including a PQI field, in order toreduce a DCI payload size, joint encoding between at least two needs tobe taken into consideration.

In other words, to support the dynamic switching of an NR-PDSCH beam maybe similar to a coordinated multiple point (CoMP) DPS in the spec.influence viewpoint.

Accordingly, there is proposed to support an NR-PQI in an NR-PDCCH. EachNR-PQI state indicates a CSI-RS resource ID QCLed with PDSCH RE mappingfor the PDSCH beam indication in addition to CoMP.

That is, a UE may be assumed to have a spatial QCL assumption from CRIindication in each NR-PQI state which may be updated by MAC controlelement (CE) signaling.

If one of NR-PQI states indicates a default mode not having CRIindication, it is assumed that a UE has the same spatial QCL assumptionbetween the DMRS of a PDCCH and the DMRS of a PDSCH.

An NR-PQI included in DCI may be used as follows with respect toNR-PDSCH beam indication.

In each NR-PQI state, a spatial QCL link for a CRI is provided forNR-PDSCH Rx beam indication.

One of the NR-PQI states is used for a default mode assumed to have thesame spatial QCL assumption between the DMRS of a PDCCH and the DMRS ofa PDSCH.

Each NR-PQI state may be updated by MAC-CE signaling.

That is, as described above, NR PDSCH beam indication newly defines anNR-PQI, and each NR-PQI state may be indicated/configured through theNR-PQI.

If a default mode (i.e., if the same beam is applied to a PDCCH and aPDSCH) is indicated in the NR-PQI states, a UE assumes the DMRS of aPDSCH and the DMRS of a PDCCH to be the same spatial QCL assumption. AneNB previously indicated/configure it.

The bit side of the PQI field may be increased by an eNBindication/configuration (e.g., RRC signaling) by taking intoconsideration a CoMP operation.

Furthermore, one part, such as the PDSCH RE mapping, QCL configurationof the PQI state description may be omitted or updated through MAC-CEsignaling.

FIG. 11 is a flowchart showing an example of a method of transmittingand receiving a plurality of signals using different Rx beams, which isproposed in this specification.

First, a UE receives a beam reference signal used for beam managementfrom an eNB through a first Rx beam (S1110).

Thereafter, when beam reporting is triggered, the UE reports, to theeNB, a measurement result according to the beam reference signal(S1120).

Thereafter, the UE receives, from the eNB, control information relatedto the determination of a second Rx beam for receiving a specific signal(S1130).

For example, the specific signal may be a physical downlink controlchannel (PDCCH). Hereinafter, a PDCCH is described as an example.

Specifically, the control information may indicate a resource quasico-located (QCL) with the resource of a demodulation reference signal(DMRS) for the PDCCH reception, as described above.

Furthermore, the resource quasi co-located (QCL) with the resource ofthe demodulation reference signal (DMRS) for the PDCCH reception may bea resource of the beam reference signal.

The above-described resource may be an antenna port, a beam direction,an arrival angle, etc. as described above.

Furthermore, the control information may be represented as a bitmap.

Furthermore, step S1120 may include the following procedure.

That is, the UE may receive the control information through 2-stepsignaling.

First, the UE may receive, from the eNB, information on a given numberof beam sets for receiving the PDCCH through first signaling.

Priority may be configured with respect to each of the given number ofbeam sets.

Furthermore, the UE may receive, from the eNB, information indicating aspecific beam set configured for each specific time unit through secondsignaling.

In a detailed procedure of step S1120, the first signaling, the secondsignaling may be layer 1 signaling (L1 signaling), L2 signaling or L3signaling.

Thereafter, the UE receives the specific signal through the second Rxbeam based on the received control information (S1140).

In this case, if the UE receives, from the eNB, a plurality of specificsignals through different symbols included in a specific time domain,the control information may be configured for each specific resource andreceived from the eNB.

In this case, the specific resource may mean a PDCCH or a CORESET.

The specific time domain may include at least one time gap determined bytaking into consideration at least one of the decoding time of thecontrol information or beam switching latency between Rx beams for thereception of a plurality of PDCCHs.

Additionally, the UE may transmit, to the eNB, UE capability informationindicating the capability of the UE related to the beam switchinglatency. A corresponding step may be performed prior to step S1110.

Furthermore, if the at least one time gap is included in the specifictime domain, the UE may receive, from the eNB, information related tothe at least one time gap.

In this case, the information related to the at least one time gap mayinclude at least one of the number of time gaps included in the specifictime domain or duration of the time gap.

Furthermore, if the eNB has updated information related to a beam basedon the beam reporting of the UE, the eNB may transmit, to the UE, aconfirm message for providing notification of the updated informationrelated to the beam.

Additionally, the UE may receive, from the eNB, information on an Rxbeam related to the PDSCH reception, which will be described in FIG. 12later. In this case, contents described in FIG. 12 may be applied toFIG. 11.

FIG. 12 is a flowchart showing an example of a method of indicating aPDSCH Rx beam using a physical control channel, which is proposed inthis specification.

The above-described contents of FIG. 11 may also be applied to FIG. 12.

That is, the following contents may be performed after the contents ofFIG. 11 or the following contents may be separately performed.

A UE may receive, from the eNB, indication information indicating athird Rx beam for receiving the PDSCH (S1210).

Thereafter, the UE receives a physical downlink shared channel (PDSCH)from the eNB based on the indication information (S1220).

Step S1220 may be performed prior to step S1210.

The indication information may indicate a pre-configured Rx beam or mayindicate the same Rx beam as the second Rx beam.

The pre-configured Rx beam may be represented as a default Rx beam. Thesecond Rx beam may indicate an Rx beam for receiving a PDCCH.

The UE may receive, from the eNB, the PDSCH after a specific offset fromtiming in which the indication information was received. The specificoffset may be determined by taking into consideration at least one of adecoding time for the indication information or beam switching latency.

General Apparatus to which the Present Invention May be Applied

FIG. 13 illustrates a block diagram of a wireless communication deviceaccording to an embodiment of the present invention.

Referring to FIG. 13, a wireless communication system includes an eNB(or network) 1310 and a UE 1320.

The eNB 1310 includes a processor 1311, a memory 1312, and acommunication module 1313.

The processor 1311 implements the functions, processes and/or methodsproposed in FIGS. 1 to 12. The layers of a wired/wireless interfaceprotocol may be implemented by the processor 1311. The memory 1312 isconnected to the processor 1311 and stores various types of informationfor driving the processor 1311. The communication module 1313 isconnected to the processor 1311 and transmits and/or receiveswired/wireless signals.

The communication module 1313 may include a radio frequency (RF) unitfor transmitting/receiving a radio signal.

The UE 1320 includes a processor 1321, a memory 1322, and acommunication module (or the RF unit) 1323. The processor 1321implements the functions, processes and/or methods proposed in FIGS. 1to 12. The layers of a radio interface protocol may be implemented bythe processor 1321. The memory 1322 is connected to the processor 1321and stores various types information for driving the processor 1321. Thecommunication module 1323 is connected to the processor 1321 andtransmits and/or receives a radio signal.

The memory 1312, 1322 may be positioned inside or outside the processor1311, 1321 and may be connected to the processor 1311, 1321 by variouswell-known means.

Furthermore, the eNB 1310 and/or the UE 1320 may have a single antennaor multiple antennas.

FIG. 14 illustrates a block diagram of a communication device accordingto an embodiment of the present invention.

Particularly, FIG. 14 is a diagram illustrating the UE of FIG. 13 morespecifically.

Referring to FIG. 14, the UE may include a processor (or digital signalprocessor (DSP)) 1410, an RF module (or RF unit) 1435, a powermanagement module 1405, an antenna 1440, a battery 1455, a display 1415,a keypad 1420, a memory 1430, a subscriber identification module (SIM)card 1425 (this element is optional), a speaker 1445, and a microphone1450. The UE may further include a single antenna or multiple antennas.

The processor 1410 implements the function, process and/or methodproposed in FIGS. 1 to 12. The layers of a radio interface protocol maybe implemented by the processor 1410.

The memory 1430 is connected to the processor 1410, and storesinformation related to the operation of the processor 1410. The memory1430 may be positioned inside or outside the processor 1410 and may beconnected to the processor 1410 by various well-known means.

A user inputs command information, such as a telephone number, bypressing (or touching) a button of the keypad 1420 or through voiceactivation using the microphone 1450, for example. The processor 1410receives such command information and performs processing so that aproper function, such as making a phone call to the telephone number, isperformed. Operational data may be extracted from the SIM card 1425 orthe memory 1430. Furthermore, the processor 1410 may recognize anddisplay command information or driving information on the display 1415,for convenience sake.

The RF module 1435 is connected to the processor 1410 and transmitsand/or receives RF signals. The processor 1410 delivers commandinformation to the RF module 1435 so that the RF module 1435 transmits aradio signal that forms voice communication data, for example, in orderto initiate communication. The RF module 1435 includes a receiver and atransmitter in order to receive and transmit radio signals. The antenna1440 functions to transmit and receive radio signals. When a radiosignal is received, the RF module 1435 delivers the radio signal so thatit is processed by the processor 1410, and may convert the signal into abaseband. The processed signal may be converted into audible or readableinformation output through the speaker 1445.

The aforementioned embodiments have been achieved by combining theelements and characteristics of the present invention in specific forms.Each of the elements or characteristics may be considered to be optionalunless otherwise described explicitly. Each of the elements orcharacteristics may be implemented in a form to be not combined withother elements or characteristics. Furthermore, some of the elementsand/or the characteristics may be combined to form an embodiment of thepresent invention. Order of the operations described in the embodimentsof the present invention may be changed. Some of the elements orcharacteristics of an embodiment may be included in another embodimentor may be replaced with corresponding elements or characteristics ofanother embodiment. It is evident that an embodiment may be constructedby combining claims not having an explicit citation relation in theclaims or may be included as a new claim by amendments after filing anapplication.

The embodiment according to the present invention may be implemented byvarious means, for example, hardware, firmware, software or acombination of them. In the case of an implementation by hardware, theembodiment of the present invention may be implemented using one or moreapplication-specific integrated circuits (ASICs), digital signalprocessors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), field programmable gate arrays(FPGAs), processors, controllers, microcontrollers, microprocessors,etc.

In the case of an implementation by firmware or software, the embodimentof the present invention may be implemented in the form of a module,procedure or function for performing the aforementioned functions oroperations. Software code may be stored in the memory and driven by theprocessor. The memory may be located inside or outside the processor andmay exchange data with the processor through a variety of known means.

It is evident to those skilled in the art that the present invention maybe materialized in other specific forms without departing from theessential characteristics of the present invention. Accordingly, thedetailed description should not be construed as being limitative, butshould be construed as being illustrative from all aspects. The scope ofthe present invention should be determined by reasonable analysis of theattached claims, and all changes within the equivalent range of thepresent invention are included in the scope of the present invention.

INDUSTRIAL APPLICABILITY

The signal transmission and reception methods using a beam in a wirelesscommunication system of the present invention have been illustratedbased on an example in which it is applied to the 3GPP LTE/LTE-A systemand 5G, but may be applied to various wireless communication systems inaddition to the 3GPP LTE/LTE-A system and 5G.

1. A method of performing beam recovery in a wireless communicationsystem, the method performed by a user equipment (UE) comprising:receiving, from a base station, a beam reference signal (BRS) used forbeam management; transmitting, to the base station, a control signal fora beam failure recovery request when a beam failure event is detected;and reporting, to the base station, a beam measurement result in aspecific resource when beam reporting is triggered, wherein the controlsignal comprises indication information indicating whether analternative beam is present, and wherein the alternative beam is areference signal having higher channel quality than specific channelquality among reference signals configured for the beam management. 2.The method of claim 1, wherein the specific signal is a physicaldownlink control channel (PDCCH).
 3. The method of claim 2, wherein thecontrol information indicates a resource quasi co-located (QCL) with aresource of a demodulation reference signal (DMRS) for the PDCCHreception.
 4. The method of claim 3, wherein the resource quasico-located (QCL) with the resource of the demodulation reference signal(DMRS) for the PDCCH reception is a resource of the beam referencesignal.
 5. The method of claim 2, wherein receiving, from the basestation, the control information comprises: receiving, from the basestation, information for a given number of beam sets for receiving thePDCCH through first signaling; and receiving, from the base station,information indicating a specific beam set configured for each specifictime unit through second signaling.
 6. The method of claim 5, whereinpriority is set for each of the given number of beam sets.
 7. The methodof claim 2, wherein the specific time domain comprises at least one timegap determined by taking into consideration at least one of a decodingtime of the control information or beam switching latency betweenreception beams for the reception of a plurality of the PDCCHs.
 8. Themethod of claim 7, further comprising: transmitting, to the basestation, UE capability information indicating a capability of the UErelated to the beam switching latency.
 9. The method of claim 8, furthercomprising: receiving, from the base station, information related to theat least one time gap, wherein the information related to the at leastone time gap comprises at least one of a number of time gaps included inthe specific time domain or duration of the time gap.
 10. The method ofclaim 1, further comprising: receiving, from the base station, a confirmmessage for providing notification of updated information related to abeam if the information related to the beam is updated based on the beamreporting.
 11. The method of claim 1, wherein the control information isrepresented as a bitmap.
 12. The method of claim 2, further comprising:receiving, from the base station, indication information indicating athird reception beam for receiving a physical downlink shared channel(PDSCH); and receiving, from the base station, a physical downlinkshared channel (PDSCH) based on the received indication information. 13.The method of claim 12, wherein the indication information indicates apreconfigured reception beam or indicates a reception beam identicalwith a second reception beam.
 14. The method of claim 13, wherein thePDSCH is received after a specific offset from timing in which theindication information is received, and wherein the specific offset isdetermined by taking into consideration at least one of a decoding timefor the indication information or beam switching latency.
 15. The methodof claim 1, wherein the specific resource is a PDCCH.
 16. A userequipment transmitting and receiving a signal through at least onereception beam in a wireless communication system signal, the userequipment comprising: a radio frequency (RF) module configured totransmit and receive radio signals; and a processor functionallyconnected to the RF module, wherein the processor is configured to:receive, from a base station, a beam reference signal used for beammanagement through a first reception beam; report, to the base station,a measurement result based on the beam reference signal when beamreporting is triggered; receive, from the base station, controlinformation related to a determination of a second reception beam forreceiving a specific signal; and receive the specific signal through thesecond reception beam based on the received control information, whereinwhen a plurality of specific signals is received through differentsymbols included in a specific time domain, the control information isconfigured for each specific resource.